This has been answered thousand of times,also some guys have posted guides etc..

There are many techinques.most heavy uploaders are using scripts.

But from what i have read and i came in the conclusion:
Unique Uploads, Not Spam
Unique Threads,Not Picture,info,link.
Find 2/3 high traffic community forums.
If you want buy a multiposter and add 7777 forums.But it will not make any difference than the 2/3..Its like 2/3 > 7777..