Pain in the neck Erebus minion build
Been playing this build with good results online now, and it is also exceptionally wonderful against DGs with poor anti-creep abilities. (Sedna)
As always, basic tactics won't be discussed, just an overview on the build and some generalities of ideas to try.
You are in for a bit of a rough start, but you can get to level 2 without dying if you are even a little bit skilled. 
So why this build? A mob of developed nightcrawlers is awesome. You can deny your enemy from going places and sitting still while you leisurely avoid DG combat and do other things until it is time to feed on them.
1) None (Yes, really, save that point)
2) Coven 1 + Improved Conversion Aura 1
3) Bite 1
4) Save
5) Coven II + Improved Conversion Aura 2
6) Bite II
7) Save
8) Coven III + Improved Conversion Aura 3
9) Bite 3
10) Bite 4
11+) I usually choose between morale and poisoned blood depending, and you naturally want army of the night at 15.
Items: Life and Speed, a mana helm later.
Favor item, horn of battle... whats better than a bunch of nasty little critters whittling down enemy DGs and towers? Rapidly regenerating nastly little critters once they think the situation is under control.
You may be asking why you don't take bite at level 1? Easy, this is a minion build, and the 2 nightcrawler skills + horn of battle make it very hard for an enemy to farm the lane you are in once you are level 2. As creeps die, more nightcrawlers are attacking them. Ignore them and keep farming, and suddenly you can't 1vs1 Erebus anymore and you are kicked out of the lane to your base when he comes for you. Trying to take the nightcrawlers down is even more futile for most DGs, as there is always more coming.
Also, suddenly having bite at level 3 often allows a surprise kill... as the enemy was worrying about minions, and now suddenly the difference in hit points changes by 500 and he cannot escape as fast. 
The great thing about night cralwers is that as long as death is happening around you, you have an endless supply of free grunts ready to sacrifice themselves for the cause.
This is also not a very mana intensive build, allowing you to concentrate on life and speed. This is doubly true since you are taking bite levels later than typical builds, thus also giving you time to buy items before you get to the higher levels of bite.
This build is also useful against a tower rook. Build up a nightcralwer wave, send them in and target the rook. When health starts to get low on the nightcrawlers, use horn of battle. Repeat. You will slowly wear the rook down without any risk to yourself. You don't even really need to be there either, that is until the next creep wave starts dying on his towers.
Overall strategy:
1) Stay out of battle with DGs until they are going to die horribly by you and the nightcrawlers if they get bitten. Try and time your arrival so they aren't so hurt that they turn tail and run, but are hurt enough that if the bite lands you and the minions can do horrendous damage while their armor and speed is down.
2) Your minions don't need to be in the lane with you when there is no DG present (but always have an exit strategy in case one becomes present)... For example, you could premptively park them by a flag an enemy DG might want to capture while you continue to leisurly tear apart creeps. It is most pleasing to see Sedna arrive at said flag and say "You suck" and then sulk away.
3) Tower busting... at first you'll want to choose towers in the creep lane so you can replenish your casualties. The great thing about horn of battle is it is great(er) against weapon upgraded towers. The AOE hits all your creeps, you use horn of battle.... and the AOE keeps hitting all your creeps... and so what? Sure they may eventually die, but there is always another wave ready to be had with a few strokes of the sceptre.
As you get to a higher level you'll have enough night cralwers and idols to simply vaporize one tower, farm, and repeat...
4) We aren't using bat form in this build, so be cautious, be healthy, be fast, and have a wand of speed ready. When in doubt let the minions do battle and observe, waiting for an opportunity to bite.