Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Threats to Tristana with this build
Tristana has been a strong champion for months now, and right now I think she's one of the strongest ADC's both in competitive play and solo Q. Her weakness is her weak early-game where she can get bullied and set behind when matched against stronger early-game champions such as Lucian and Miss Fortune, who right now have received a few nerfs that have made them a little less common.
Tristana's mid-game is very strong and her late-game is definitely among the strongest of any AD carry. Rapid Fire can give her extremely high DPS for a limited duration, she gets a lot of burst with Explosive Charge and Buster Shot, and she's an extremely safe champion with her extremely high range ( Draw a Bead will give her the highest permanent attack range in the game) and resettable, long distance dash, Rocket Jump.
I think these factors more than make up for her early-game weakness, which is in itself not too weak. She has some good matchups, especially at level 6 which is a huge power spike for her while not always such a big power spike for other ADC's.
And above all, the biggest reason to play Tristana is she's so damn fun. Getting resets on her W is such a fun mechanic to have on an ADC, and since her preseason changes that make it reset on her E that's only become more fun to play around. Whether she's average or strong, suited to the meta or not, she'll always be one of my favourite ADC's to play just because of her playstyle.
Tristana's passive is Draw a Bead, which increases her attack range after each level. This passive makes her an autofiring ultralong-ranged beast at level 18. The passive also effect her other abilities, such as Explosive Charge and Buster Shot
Rapid Fire (Q)
Her first ability is the Rapid Fire. This ability increases her attack speed for a short period of time. If you already have Phantom Dancer and Statikk Shiv, you will go super-sayan if you activate Rapid Fire. The cooldown now also gets reduced by 1 every time you autoattack an enemy who has the bomb from Explosive Charge.
Rocket Jump (W)
Her second ability is Rocket Jump. This ability is mainly used for 3 different reasons:
1. You got caught and need to get away.
2. Someone you nearly killed is escaping, and you need to close the distance.
3. You want to farm a huge wave of creeps more easily, so you might consider to stomp on them.
The cooldown of this ability is also reset when you get a kill or assist, which might get in handy.
Explosive Charge (E)
Her third ability is the Explosive Charge, which has both an active and a passive function:
When you trigger the active you shoot a single bullet, which stays on the target for a few seconds. You can stack the passive by shooting at the enemy, until it explodes and deals area damage after four shots.
The passive makes it possible to deal damage to nearby enemies when you kill an enemy.
Buster Shot (R)
The fourth ability is the ultimate, and its called Buster Shot. This ability makes it possible for Tristana to fire a massive shot at a nearby champion to deal massive magic damage and push the champion back. If there are anyone in the knock-back area, they are pushed back as well.