Pros
+ Great defender with solid damage
+ Should get #1 or #2 by end of each match
+ Great chances for multi-kills

Cons
- Easy to be ganked when pushing a lane from above
- Very reliant on team mates to do the right thing and cap the other 2 bases and lave bottom lane alone
- Slow to escape

My name is r3dpony and this is my first guide. Feedback is welcome! So far, this build has played very well for defense on the bottom lane in Dominion.

Passive Techmaturgical Repair Bots: HP regen aura which helps your minion wave push

H-28G Evolution Turret: Heim's main offensive and defensive weapons that which deal a lot of damage. Most players ignore these, which is a bad idea for them (good for you!)

Hextech Micro-Rockets: As the game goes on, these start to deal a good amount of damage. They are also nice to disrupt multiple champs attacking your base at once.

CH-1 Concussion Grenade: The blind and stun of this attack is key. 3 seconds under your two turret and the base will have any champ begging for health (and probably waiting on a respawn). This is why we max this out first after our guns.

UPGRADE!!!: A quick boost to turrets will make quick work of anyone who finds themselves between two or your guns!

Greater Mark of Insight - Magic penetration is always a good thing!

Greater Seal of Potency - Added ability power will help your damage output.

Greater Quintessence of Insight - More magic penetration for good measure.

Greater Glyph of Focus - Reduced the cooldowns for fast damage output.

Promote
Pushing the lane is much easier with this spell. Keep with your minions and pop it when the health is low for best results.

Garrison
Garrison will help you defend your point and rack up kills. Used with hourglass, a quick cast of garrison / upgrade / hourglass and you will mow people down.

Rush the Rod of Ages in the start to get a nice boost throughout the match. The passive will kick in a good deal with all of the exp you get in dominion.

Next up is hourglass. This is your key item when defending. Once you have it, you should be able to take down groups of 1v1, 1v2, and 1v3 with the right timing. Just pop garrison, upgrade, and then hit the hourglass. Watch the kills roll in!

Some nice shoes to help with magic penetration and speed!

Some much needed health and more AP.

And finally, you should be able to grab this towards the end of the game. Nobody should be able to take your bases at this point!

Heim is not an offensive powerhouse, but when players come to you, you can lay waste. If nobody is coming your way, just slowly push the bottom lane with your minions and turrets. If they ignore you and leave you 1v1, you will get some a few easy caps as the minions will overrun the other player.

Your main goal is to make sure you hold your base at all costs. Getting ganked in the middle does nobody any good (expect the other team).

If you play safely, you should end up with a 2-3 caps and a good number of kills with the team avoiding any base you stand near.

The key attack sequence (as noted above) is to draw players into your base. Have two turrets set up in spots where they can hit the oncoming players (but not too far out from the center of the base). Cast Garrison, Upgrade, and Hourglass and watch the carnage. When hourglass fades, pop missles and stun anyone who is left standing.