Leashing Blue:
while protecting and leshing blue you can put the turret at the edge of entry bush and walk away and be safe from ganks, from here you have 2 options see if your jungler is getting leash by other laner and if the other jungler is someone like amumu thats starts blue if so(and this trick only applies in lower elos) just go and put your turret in wraith area just behind where the big wraith will spawn at 1:38, walk behind the wall and hit a couple and you stole the big wraith and have set enemy jungler behind.
If no one is giving leash to jungler then you can put your turret down from the wall to the left of exactly where the blue golem spawn.
Now just go back and lane, always remember, you must not put the turret in any place where it can constantly hit the minions or you will push the lane hard and will be vulnerable to ganks if scared put the turret in bush from where enemy jungler can come in.

At level 6 put both your turrets in middle of lane and back keep and buy charlice and a ward, keep an eye if the enemy is about to kill your turret press R and let them have a couple of extra shots.

Heimer can solo dragon at level 9 very easily, when coming back to lane post level 9, keeping in mind your turrets would have already pushed the lane while you were backing just go to dragon area with the jungler if he comes and with a ward, put the ward where you feel it will keep you safe and put the both turrets next to dragon and get its agro out and then move back and let the turrets hit the **** out of him, use R to save the first turret right before it dies, the dragon should die without killing second turret.

Dont try to flash and help your jungler to gank your lane, chances are your missiles will just hit the creeps unless you activate your ulti to get 5 missiles.

Dont fight near wraiths and wolves be aware that your best weapon is W you cant let it go to waste.

Dont be afraid to spam ulti even if it is just to save the turret and let it land a couple more shots and die while you are backing.

Get your team to play poke battle and push hard frankly heimer is OP in this respect, when pushing turrets no one can stop a team with heimer coz you can just spam W, E all day and be a pain in the a$$.

Always harass your opponent in lane for even a single CS whenever their are 2 minions left in the wave use W to harass hard

kassadin: You just cant do any thing except spamming pots to be able to lane

Fizz: A good fizz will destroy you so just dont.

Le blanc: passively farm for first 20 minutes and make sure you dont die then you can just work with team and she will be useless

Morde: farm lane and run dont try to harass him waste of mana

Malzahar: stay at safe distance and dont let him combo you to death.

Boots+3
Charlice + pots+ ward
Athenes
Needlessly large rod
Dcap
giant belt
Rylai+ Amp tone
Glacial Shroud + blue pot
Void staff+ Frozen heart

Frozen heart is just recomended if they have champs like xin zhao or irelia and no one on your team got it, it is replaceable by thornmail if they have someone like trist and cait may be or mostly by banshee's veil if they are very AP heavy or GA if they have mixed damage and you have a team with huge threats and if you are way ahead just get a zhonyas hourglass.