Hi I am Sam5max. This is my first guide I ever created, I hope you enjoy it. The first champion I ever played was Tristana. However, I have recently discovered AP Tristana. Possibly a bigger snowballer then Leblanc. She is super fun. This guide is about how to pwn everyone's face of with Tristana.

Pros:
UBER fun
Best catchphrase (I wanna shot something!)
Great farming with rocket jump
Free to get by liking LoL on Facebook
Extreme mobility, via rocket jump
Is a yordle
Extreme burst
Even more extreme AP ratios
Coolest skins

Cons:
Kinda squishy
Scales of late game
Focused in team fights (Until you grab the zhonana's hourglass)
Needs a fed AP carry to reach full potential
People think your trolling

Yes this needs a whole chapter on it. This is because there are several different ways to burst.

Levels 2-5 burst:

WARNING: Do not use this if the enemy has a better burst then you, or will deal more damage to you
Wait until they are standing by their mages. Then rocket jump, and explosive shot in mid air. There will be two outcomes:
1. If they retreat to dodge rocket jump then you still should of hit them with explosive shot and killed off all the mage minions. Run away before they can harass back
2. If they stay still and get hit by rocket jump then you will deal tons of damage when combined with the deaths of the minions (From explosive shot's passive).

Levels 6-when laning stage ends:

Same thing as 2-5 except you want to use your ult when they have around 300 health left

Team Fights:

Rocket jump once you spot a squishy and use explosive shot. Activate Zhonya's Hourglass and let your team weaken the enemies for the two seconds. Once out of stasis use your ult on whoever needs finishing off. From there you have two choices:
1. Use rocket jump to get out of the fight if you are low on health
2. Rocket jump to the next lowest person and focus them until they die. Then you can chose to do step 1 or do step 2 again.

Starting Items:

Boots of Speed + 3x Health Potions
This is my favorite for Tristana. It generally provides enough sustain to get to level 6 and speed to dodge skill shots. Upon reaching level 6 just combo, kill then head back to base to buy more stuff.
Doran's Ring
I used to use this. Good if you use your ability's a ton and need the mana regen. The health is good against burst champions but I generally perfer boots of speed and the health pots for the sustain.
Amplify Tome + 1 Health pot
I don't really like this combo. Sure the AP is good from the Tome but you don't have very much sustain with only one health pot. Plus, you only really need the AP at level 6. Good if you play very aggressively.

First Trip back to shop:

Here are the items you could buy when you go back to spawn for the first time.
Needlessly Large Rod
If you have enough for this item on the first trip back to spawn, buy it. Your damage increases like crazy. This is almost always the item that you first want

Blasting Wand
Now you may be saying, "The first item to buy is the Zhonya's Hourglass, and that does not require a Blasting Wand!" You would be right with that statement. However, it still increases your AP which is something that you always want to be doing so that you can snowball and burst people down really fast. Plus, it is useful for your deathcap afterwards.

Kage's Lucky Pick Kage's Lucky Pick
This item is okay. I really only grab it if I am having a really bad early game. Otherwise I don't bother since you need to rush other items first.

Sorcerer's Shoes
I don't usually get this since the blasting wand is a better item to get, but if you don't have enough then this might be a good choice.

Boots of Speed
If you did not get these the first time I would get them, but they are not as important as a blasting wand or a needlessly large rod

Doran's Ring
If I have an extra 475-500 and I already have boots of speed I sometimes buy this. Helps increase ability power a tiny bit, which is always useful. Also provides a little bit more sustain.

Other items to spend the rest of your money on once you buy one of these items and have money left over:

Sight Ward

Core:

Why I take Zhonya's Hourglass before Rabadon's:

I find Zhonya's essential for team fights. Those two seconds of immunity can turn a death into a pentakill. The reason for this is because when you rocket jump in and kill off someone, you imediatly get focused. With 2 seconds of immunity your team can weaken the others and then you can just rocket jump from enemy to enemy killing them all.

When to buy some better shoes:

I will generally wait untill I have both the zhonya's and rabadons. The reason for this is because you need AP. If you slow yourself down by buying a tier 2 boots before then you might not be able to kill the enemies in one burst. If this happens it is pretty hard to recover. It is always a race between your AP building and their health/magic resistance building.

Endgame

I take 21-9-0 for masteries. The 21 is offensive to help with the burst and make it even more stronger. I take 9 in defense since you don't really need runic affinity because tristana doesn't benefit to much from any buffs.

My rune choices are pretty simple. I take:
Greater Mark ofMagic Pen Marks: to get through early magic resistance
Greater Seal ofMana Regen Seals: to never run out of mana
Flat AP Glyphs: So that our burst is ever bigger
Greater Quintessence PotencyFlat AP Quints: Because there is no such thing as too much AP (Except when against a viager)

Great Choices:

Flash:
Really great life saver for when rocket jump is down. Also, flash is better then rocket jump for escaping due to the face that while rocket jump gets you places faster, flash is the quickest thing possible. If you are really getting bursted because you ran into a giant trap, use flash over a wall. Flash has no traveling animation, or warm up time, thus making it faster.

Ignite:
Good for grabbing killing in early game. Also good for killing people with low health. Ignite + Explosive Shot will make even Teemo's DOT ashamed.

Okay Choices:

Ghost:
I never really liked this spell and I don't find it that great on Tristana. Not useful if you run into a trap. Really it's only use is to run and catch up to others, but I like flash for this better because flash can be used to jump over walls and has an element of surprise

Heal:
Nice to trick others into tower diving, winning a close fight, surviving traps like Teemo's mushrooms. However I find ignite more useful.

Teleport:
I find this spell not all that great on Tristana. Sometimes good for newbies to Tristana. The reason I dislike this is because you once you burst, you almost always make them either die or have to recall. In that time you can do the same thing and not miss out in that much.

Cleanse:
It is an okay summoner spell. It is a little bit difficult to get used to. If you are in a ranked game and see a warwick, malzahar, or skarner, I would recomend cleanse to break out of supremise.

Bad:

Exhaust:
Alright, I am probably gonna get raged at for this, but hear me out. This Tristana build focuses on killing in one burst. Exhaust provides no damage to help out in the burst. You don't need the slow since rocket jump has about the same range as exhaust. You won't need the slow because you should of killed the person. If you did not then exhaust would provide the time for maybe a couple more auto-attacks, which deals less damage then ignite since you are not building AD. Late game this spell is good against fed carry's but that is pretty much it. Good spell, not good for AP tristana.

Clairvoyance:
Pretty good spell, not really good on Tristana. It is better to just let your support take this.

Revive:
It's a bad spell. Difficult to know when to use, long cooldown, relies on you dying, doesn't help with burst. It is pretty much one of the worst summoner spells to take

Clarity:
I almost never run out of mana with only my mana regen masteries and runes. However if you are having mana troubles, getting a doran's ring would be much better choice then wasting a spell slot.

Surge:
Ignite is almost always better.

Smite:
AD Tristana is not a jungler, nevermind AP Tristana.

Promote:
Not a good spell, no burst, just last hit

Draw A Bead (Passive)
Increases Tristana's attack range by 9 every time she levels. At level 18, Tristana has 153 bonus range on her autoattacks (703 total range).
Not all that useful when you are playing AP tristana. Can be used to attack things over the walls. It can also be used to take out heirmindinger's turrets.

Rapid Fire (q)
Increases Tristana's attack speed by 30 / 45 / 60 / 75 / 90% for 7 seconds.
Kinda pointless. I activate it when taking out turrets. I also sometimes activate it in team fights for a little more damage, but don't bother if you are running low on mana. I believe that activating it will use the lich bane, (need confirmation).

Rocket Jump (w)
Tristana fires at the ground to propel herself to target location, dealing 70 / 115 / 160 / 205 / 250 (+80% of ability power) magic damage and slowing surrounding units by 60% for 2.5 seconds when she lands. On a champion kill or assist, Rocket Jump's cooldown resets.
Oh my god I love this ability. This thing is so EPIC that there is no telling just how awesome it is. This is what makes AP tristana better then Leblanc. Rocket jump can be used to hop over walls if someone is going to kill you, it can be used in your burst, if can be used to catch up to fleeing enemies, it can be used to farm. Pretty much whatever you want. When in a team fight I engage with this and explosive shot, upon landing I quickly activate zhonya's to prevent myself from being focused. After I come out of stasis I will most likely use my ult on whoever is low enough to finish off. That will cause rocket jump to refresh. At that point just jump from person to person, killing them all off. Pretty soon your team will score an ace. If at any point you are really low, you can use rocket jump to hop out of the fight and let your team finish them off.
Explosive Shot (e)
Passive: Enemies explode when slain by Tristana's attacks, dealing 50 / 75 / 100 / 125 / 150 (+25% of ability power) magic damage to nearby enemies.

Active: Explosive Shot rends the target enemy, reducing healing and health regeneration by 50% and dealing 110 / 140 / 170 / 200 / 230 (+100% of ability power) magic damage over 5 seconds.

This ability is highly underrated. This can deal more damage then your rocket jump while in laning stages, and is essential to your burst. The passive is amazing. If the enemy is hugging their mage minions during laning stages I love to rocket jump onto the person. Not only does rocket jump deal damage, but also the three mages will deal a bit of damage, since they will all die. Then you also use Explosive shot's active and deal even more damage. At only level 4 you are dealing 480 damage to one champion (not even including ability power). This brings their health down to a little bit over half most of the time. By the time you get your ult you can do this burst again and then just use your ult to finish them off. This ability combined with rocket jump can also kill off huge piles of minions in just one rocket jump. Also it can be used to clear out wraiths. Just rocket jump over the wall and hopefully you will kill all of the minions. If not focus one of the smaller minions and they will all die from the explosions from explosive shot.

Buster Shot (r)
Tristana fires a massive cannonball at an enemy unit. This deals 300 / 400 / 500 (+150% of ability power) magic damage and knocks surrounding units back 600 / 800 / 1000 distance
Tristana's ultimate. This thing has outrageous base damage and even more outrageous AP ratios. It can be used to finish off people when using the burst. I almost always use it when I know that just my ult will finish them off. Otherwise you might push them out of distance and then not get the kill and waste your ult. Whenever this is off cooldown I like to try to burst them to get the kill. This ability scales great with AP so buy lots of AP.

Laning with tristana is pretty simple. Last hit, harass, try to get to level 6. Your Explosive Shot's passive does decent damage so if you can last hit a minion near the enemy champion that is pretty good. Once you reach level six check how much damage your ultimate and rocket jump will deal. Then check the enemy's health bar, (Remember each bar = 100 health). If your burst will kill him then go for it. If not you might want to harass with rocket jump and explosive shot. The next time you do that you should be able to ult.

Always remember to check how much damage rocket jump and more importantly, your ult. I have gotten free kills from people tower hugging with really low health. I just ult them and they die. It can be pretty funny.

Whenever you go back to shop try to buy some sort of AP item. I usually like to work on my rabadons if I can. Due to Tristana's INSANE ratios when it comes to AP you will notice a huge difference with whatever you buy.

Teemo: 2/10

I love facing Teemos. I always faceroll them. Be careful with harassing them, their harass is a lot stronger. Once you reach level 6 just rocket jump and explosive shot them. This will probably lower their health to half, so next time you burst you can kill them.

Ahri: 9/10

I have found Ahri pretty difficult to beat. Be careful when harassing with rocket jump because Ahri will just burst you right back. I will add more to this once I face more Ahri's

Vladimir: 6/10

I find Vladimir kinda hard to beat. I generally let Vladimir push the lane to my turret, then I rocket jump him while he is attacking it. The rocket jump damage, plus the exploded mages will deal him tons of damage. If the Vladimir you are facing has really fast reflexes and pool's before this then don't bother. Just try and get Vladimir to go into pool early, then have jungle gank him.

Leblanc: 7/10

Leblanc can be pretty difficult to cope with. It is almost always about who can get the first kill. It seems Leblanc can dish out more damage then you early game so be careful. It is okay to trade kills with Leblanc. Your AP ratio's are higher and Leblancs generally get soulstealers. If this is the case, then trading kills will be fine because it will leave leblanc with lower AP. I recomend getting ganks from your jungler and building some health. My favorite item to get is the Heart of Gold. It provides health and 5 gold every 10 seconds. Since people mostly know tristana as a AD carry, Leblanc will most likely not build health back, thus giving you the advantage. IMPORTANT: You will almost always need a gank from your jungler. When doing this make sure that the junglers have a deacent amount of heath. If the ganker has too low health then the Leblanc will most likely just take the kill and continue laning.

I will add more to this list when I have played a few games against each champ with AP tristana.

-Use rocket jump to farm minions when no one else is around to attack.
-Just using Explosive shot can be a good harass
-Always call MIAs even if you are not sure they left your lane
-Using rocket jump over walls can help keep you alive
-Tell your team that you are playing AP Tristana. If you don't they might put to many AP's on your team.
-DO NOT tell the enemy team that you are AP. Most people think of Tristana as only a AD champion so lower level people might be fooled and might ever try and buy armor to counter. Plus it is really funny when the enemy team all of a sudden goes "Tristana is AP? Why the heck did I waste money on thornmail???"

Thanks for reading my first guide. I hope you learned something about the wonderful champion, Tristana. Please inform me what you believe I did wrong/need to add. Just remember that this is an AP tristana guide. Not an AD tristana guide. I would really love advise on what I could do better. As long as you write warm feedback I will most likely take what you say into consideration. Have fun!