So, you have come to this page seeking advice on soloing top lane with Heimerdinger.

Heimerdinger is more suited to mid-lane however people (such as myself) like to play him to annoy the enemy team.

PROS!

Can Solo Baron Nashor.
Can Solo Dragon.
Can Defend TOP or MID lane like a beast.
His 'Upgrade' ability can make your other abilities ridiculously strong.

CONS!

He is not meant to be built as a tank.
You need to be good at targeting skill-shots (Especially with your grenade [e])

Since you are a Top Laner you may find TP particularly useful in helping Bot Lane or getting back to your Lane in a hurry.

FLASH is generally expected as the second ability. But it is really up to the player to decide this (Though I do highly recommend it).

So you generally let your turrets eat away all the minions for you as they will give you the gold. Otherwise, there is no trick to farming.

After you have fully upgraded your turrets and there is no champion on your lane you can quickly go into the jungle and take out some monsters before the champion comes back. (This is especially helpful when you want additional gold AND health). If you need BLUE buff, you don't even need your jungler to help as Heimy can solo it on his own. Also if your on blue team, BLUE buff, happens to be right next to you.

Using the build I have given, you can take out Dragon fairly early if need be.

Later when you have most (if not all) of your items, you can solo Baron Nashor without the enemy team even suspecting.

This section is purely for Invading the enemy jungle with your entire team.

(Generally, the team I tend to play with is Heimy Top, Pantheon Jung, LeBlanc Mid, Jinx ADC, Mundo Supp.) We tend to sneak up into river. If there is an enemy checking for invasions, wait for them to get close to the bush you are all in. As Heimy, you won't need to do much as the rest of your team should handle it (unless it is more than one or two people checking, use your turret). Then go the the buff your jungler wants (in most cases my allied pantheon would invade for blue buff to then come back into our jungle for red). Generally the rest of the team will be there (except their top laner) and place your turret in the bush next to where the golem spawns. Anything you target in the turret's radius will also be targeted by the turret. If any champion gets too close, you turret should ward them off whilst helping the jungler take down the blue buff golem.

After succeeding stealing the blue buff, go back to the river to make sure you are safe and TP to the top lane turret and start defending like a BEATCH! (Next Chapter)

When you get to your lane, place a turret closer to your tower from where the allied minions meet the enemy minions and keep doing so until you have a purely defended area of turrets. If the enemy champ tries to jump you whilst in the radius of your turrets, stun them with your grenade and fire your rockets at them.

If and when your enemy champion dies or goes back, you do the same just to be sure that your levels will always be equal or ahead. TP back to Heimy's turrets to ensure you don't have to keep replacing them.

Whenever there is an imminent enemy gank, your enemy top laner will tend to run in. When he does this, depending on the enemy champions involved, stay your ground and stun the more threatening champion and fire the rockets so that they will hit both the top laner and jungler. This should hold them off.
However if you do feel well and truly threatened, start running back to your tower (If they are faster or have some sort of leap, use flash to make sure you get away) and place a local turret, stun them, in the radius with your 'e' and shoot them with your 'w' If you have your 'r', use that before firing off your 'w' to make sure you get the kill.

If ever your jungler comes to gank run away from your turrets to the point where they become inactive. Your enemy champ will think you have gone back and start pushing, run back to activate your turrets again, your jungler should jump in and start helping. Stun the enemy champ and fire off your rockets to secure a kill or assist.

It will get to the point where mid or bot lane may need your help. This is when your TP becomes most helpful. (Next Chapter)

With your team mates, pushing should be piss easy. Set up three turrets in the front-line of the lane you are pushing (Take mid for example). Getting to the inhibitor turret put a line of turrets in front of the turret radius, and stun anyone who gets in their radius. Fire of your rockets (preferably ulted) and take some more kills.