You send 1 peon to build a lumber mill then 4 to build the towers. (Remember to keep building peons on lumber/gold) Now build 4 towers close to the enemies base. After they're done keep building towers until the towers are destroying the whole base and if the enemy tries to stop you then the towers behind you will protect them. This won't work too well against a very good player.

This only works for orcs.

If you have any further questions just tell me, I'll contact a friend of mine that is very good at tower rushing.

JMBA Technical Solutions. For all your technical needs.