Hi. My name is Monoplex and Heimerdinger is one of my favorite champs. I also have loved the Engineer since the original Team Fortress. Go Turrets.
Heimer is a unique champ. He has the only pets/minions/summons in the game without a duration but he has no direct control over them. There is however an indirect way to get your turrets to attack an enemy champ. Counterattack! Heimer's turrets will attack an enemy champ that attacks you.
But Heimer is a squishy AP champion, why would we want to be attacked? ever? Well, someone's got to take a hit... so yeah, Offtank Heimer. Kite your enemies while your turrets do significant damage.

Heimerdinger is a surprisingly good jungler and can even go without Smite. but It speeds things up and I recommend taking it. and Without further blah blah The nitty gritty.
1 Start with Cloth Armor and Health Pots. Get Q first.
2 Go straight to the blue golem and put a turret in the corner, behind where the big guy spawns.
3 at 1:55 he magically appears and your turret immediately gets aggro and attacks the big guy. When the turret dies let the aggro come to you.
4 Place another turret. Smite. Red pot. Move on to Wolves, Wraiths, Mini Golems, Red buff.
5 Recall. Boots, more pots, and a ward or two. good luck ganking. Heimer's gank isn't great, but your best shot with E is either a long range on an still, unsuspecting target or point blank.

For your first route or two you need to tank the damage for your turret. it does way more damage than your auto attack and you need it ticking as long as the creep camp is.
For effective clearing: start auto attacking and put down a turret(at your discretion for which of you takes the aggro). When the camp is bunched up hit 'em all with e and w.

After Mercury Treads, Chalice of Harmony, and Rylai's Crystal Scepter you have a judgement call to make. If enemy casters are putting the hurt on you get BV. Melee? Frozen Heart. Need to do more damage? Rod of Ages and Deathfire Grasp.
If the game lasts this long you can sell your Chalice of Harmony and get an Archangel's staff and/or Guardian Angel because only heaven can save you now.

For the other Summoner Spell I take flash. Ghost is probably the better choice, but I just prefer being able to flash over walls to get away. Other good choices would be Clairvoyance, Cleanse, Exhaust, or Teleport. Take whatever suits your play style best.