Heimerdinger, in my opinion is still of the weaker AP carries in the game. There are just too many champions that can do so much more than he can. However, you can still play him effectively, you just need play to his strengths. Although Heimer, is physically the weakest and slowest champion in the game, all of his abilities allows him to hang back and deal damage out of harms way.

His rockets is one of the longest nukes in game, his grenade is relatively long, and you can think of his turrets as yet another extension that he can place in front of himself. In short, you want to deal as much damage as possible with out ever being touched. To do that, you need to familiarize yourself with every detail of his range, know to to play defensively, and when to play aggressively

The mastery I use for Heimer is pretty standard. It is the same mastery book I would use for almost any squishy AP Carry. I like going 21 deep into utility because It feels like Heimer is always the insta-gibb target, especially the way I build him. So it important that he can get his flash up ASAP so he can kite around.

For heimerdinger i like to take Flash and teleport as a summoner spells, because i like to solo top and then if i need to go back i always just can tp back so i dont lose to much. But i can also go with a flash and ghost so i have easy'er with the kiting. but i my favorite is flash, tp.

When you are in lane, it is important to know where to place your turrets to be the most effective. Generally, you want to place your turrets away from your creeps if the enemy has any for of AOE. You do this so your turrets doesn't take collateral damage when they are nuking your creeps. Also you want to know the AOE range of the enemy so you never stack 2 turrets close enough so that they can nuke 2 turrets with 1 spell. On the flip side, if the enemy is a single target champion like Ezreal, you want bury it in with your creep line so he can't snipe it

I usually like to place the turrets right where the creep would meet so the creeps do not attack my turrets or stop when my creep wave meets theirs. I usually tactically place my turrets to form a barrier too! Hypothetically, if I am blue side. I would ward the curved brush on the between the enemies ancient golem and the middle divider. Then I would place 2 turrets on the right side of the creep line. What this does is it creates a safety barrier I can retreat to. I have vision on the right and I have turret protection on the left.

I think heimerdinger is one of the best farmers in the game and there is different ways to farm in different levels, from fx 1-6 i nearly only use turrents cause of the rocckets dont do that much dmg and if i like finish a creep up i can just use a auto hit.
6-12 i use rockets and turrents cause of the rockets can anyways 1 shot the caster minion behind and then the turrents take the front minions.
12-18 i only use rockets and grenate in a lane and then my turrents is in a different lane and farming there then i get the most gold our of it as possible.

The most hated champs for heimerdinger i would say its gonna be:
1. Caitlyn: i hate caitlyn because of her range and all the caitlyns i fight agianst always kills the turrents the second its come up.

2. Morgana: i hate morgana because she just use her "Tormented soil" and then they nearly allways die and i lose all my mana when i need top put a new up all the time.

3. Brand: just like Morgana use his "Pillar of flame".

4. Nunu: Eats my turrents all the freaking time ;( ....

and then there is much more but i it would be boring to read about. ;)

The way I play Heimer Early game is really aggressive. My whole philosophy is that if I can get hits on a champion I will do it. Once you get any champion under about 50% health, it opens up that lane for an easy gank. That puts tremendous pressure on them and they will either start losing last hits or risk dying. What I generally try to do is to go straight to the lanes and start pushing it. I would rocket and right click the first wave asap. As soon as I can start rocketing and right clicking a champion I will do it with little hesitation.

My general rule of thumb is that I am safe from jungle ganks for up to the 4 minutes mark. So my goal for that first 4 minutes is to get them so low that when a jungle does gank me, I can kill the laner then burn summoners to get away. Also, because I am pushing lanes so aggressively, I need to ward. Think of it this way. A ward is approximately 3 creeps, so if you deny the guy 3 creeps in about 4 minutes its well worth it. On top of that, every time their jungle ganks you, they are going to be wasting time.

One of the problem I know most players will face when using this build is mana problems. It is very important to manage your mana wisely, especially early game. You want to be near full mana for until level 3. Its okay to throw down a random ability if you are mana capped. But if you are, you have got to make ever point of your mana count. If you are going to drop your turrets, don't drop it to die. If you are going to shoot a rocket, make sure it hits the champion. Finally, right clicking is your friend. The wrench doesn't do much damage. But like I said earlier, it adds up!

Picking up at mid game you returned to your lane after shopping for the first time (under 10 minutes). You now have the mana to waste mana and push like crazy. The tower should be weak from early laning your minions attacking, you auto attacking, and your turret doing damage. Depending on how the game has gone thus far generally this is what has happened.

A) You are winning your lane out minion killing, out tower damaging, and maybe even a kill.
If this is the case then you should be very aggressive and finish the tower a.s.a.p. It will allow you to head to another lane to gank and push that tower down. You can leave a turret or two down if you have them to keep your lane defended for a while once you leave. It would be wise to have someone from bot to come up shortly, mid swap up top if they are struggling, or have a jungler babysit whenever possible.

B) The lane is evenly matched or only a slight edge exists one way or another.
If the lane is basically in a stalemate you should definitely call in a gank from anyone. If you can get a kill or even just weaken the enemy enough to base you will get the tower for sure. Heimer push is amazing and with another champ there from a gank the tower will surely die also factoring in it should be fairly week from pushing earlier. Move onto another lane after that just like above and take another tower.

C) You are at a clear disadvantage.
If you have over extended for to long and got ganked pushing or just got beat for whatever reason call for help. Switch lanes if you need to but otherwise get that same gank from above you can still very easily get the tower down with a sucessful gank. You can also switch to a defensive position for a few minutes just working on harassing and farming.

Heimer needs farm and an early level advantage on top of a good farm is priceless. You don't want to spend much time early roaming around since you basically have to rely on a grenade to successfully gank. Heimer rockets require 2 or less minions to hit an enemy champion unless you use your ult. Time spent wasted on missed ganks of other lanes results in a longer time destroying your top enemy tower and precious farming time. There are windows of time where Heimer can leave his lane. If you have pushed a lane hard again but are fearful of going full attack on an enemy tower you can leave the lane at that point to go get your blue buff. By the time you return to the lane it should have stabalized and this time with blue buff you can't be stopped.

Late game for Heimer is about 25 minutes. He is still going to be strong at this point. But not much longer. He still start falling off once an enemy carry can 2 shot his turret. So basically want to either win this in the next 10 minutes or be so far a head that you can't lose this.

Playing with a Heimer on your team almost always forces you to play like you are using a poke comp. Heimer is great at doing 1k burst damage with his grenade an rocket combo then backing to his turret's safety. This is also a requirement of your team. You and your team should be playing like you are playing dodgeball. You want to set up your two turrets near where you thing the team fight is going to happen. When your CD's are up, you are safe to run the enemy's line to attack. The moment you lose that ball (your abilities are on CD), you run back to your side. You do this to pull the enemies or force them to engage and then you back up into Heimer's turrets.

Fighting on Heimer's turrets is probably one of the best position you can get. It really not up to you to do this and more your team, but when a team fight breaks out. Heimer need to back behind his turrets and his allies also needs to collapse back on him to pull the enemy before engaging on a full fight.

Sometimes, Heimer can't really set up his turrets prior to fighting. His best alternative is to throw his concussion bomb and rocket and immediately drop the turrets right behind his allies slightly in the enemy's range. Throwing the concussion bomb first and dropping the turrets at the same time creates a momentary safety barrier and makes it slightly less risky to be in firing range.