The art of Heimerdinger isn't early game. He's somewhat frail and very mana hungry if you spam rockets all day. No. The key to the **** is Rylias. As soon as you get Rylias the game might as well be over. Teamfighting? Place a couple turrets down and everyone will be slow for seemingly no reason, allowing easy picks or escape. Once you get it, then your turret radius becomes the titular "Zone of ****" that no one will want to go into if there are other champions nearby.

Your main tool for poking is the rockets. But you can't go firing them all over the place, you have to make your shots count. So a good strategy is to slow them with the Zone of **** (or simply bait them into attacking a turret) then fire. Your grenades are also good for landing rockets once you stun them. You might want to take grenades even earlier than I suggest, based on the cc potential of them.

Place turrets closer to tri bush and the jungle bush, the usual ganking spots. Once that is accomplished, you will notice that junglers tend to ignore them when ganking. This is free damage that will be essential to your survival. Once you get Rylias you are essentially ungankable. You can also place turrets in bushes for free vision. But these will quickly become targets. Setting up poke opportunities. Later in the game, try placing turrets along walls and far apart to get as much **** Zone coverage as possible.

The ADC might hate you more than the enemy team. This can't be helped. As a ****er you thrive on turrets, and turrets aren't very smart. They'll attack minions and even kill them. If your ADC is a crazy person who only cares about CS (as most ADCs are) then you might have to win them over with your amazing skills and abilities as a ****er. If possible, try pairing up with someone that has a bit of cc such as a snare or stun or even slow. It'll make landing those grenades a lot easier than you first though.

The enemy will seem to ignore the turrets at first, but then it will become their life's passion to destroy them. Every time you put a new one down, they will be horribly distracted by its presence. They will walk over almost instantly to AA it without remorse, those heartless fools. Little do they realize that whenever one of your other spells hits an enemy, a beam fires out from nearby turrets, and that beam hurts if you're not expecting it.

Passive: ****er gets fast whenever he walks toward one of his turrets while inside its vicinity. Might be useful for escape.
Q: Turret that you place down. Kind of small attack radius. Make the enemy walk into their range to attack you. But be careful! The turrets will almost always attack minions instead of champions first. So land another ability or AA them for more accurate results
W: Rockets that fire toward your cursor where they intersect, if they have more range left, they will continue along your trajectory. If you are less likely to hit the enemy, then try to get them to cross earlier, they will spread out more and hit more things, at the expense of concentrated damage.
E: Grenade that stuns in the center of its AoE. Good stun and utility. Very neat. Use for poke or whenever you feel like it.
R: Upgrades one of your abilities.
Upgraded turret is good in teamfights or when you need some zoning
Upgraded missiles are amazing and can burst someone down who isn't expecting them
Upgraded grenade can stun a lot of people, but is tough to land
Upgraded ultimate doesn't exist I just thought this fourth line looked better