in case any of you have't seen the tips from Inside Xbox, here are details on two proven rush techniques.
Warthog Rush:
Description: Warthogs can be trained at your base center eliminating the need for extra training facilities. This saves money and allows you to quickly ready a sizeable army of Hogs to take down your opponent. This strategy works best with Cutter or Anders as Forge's supply pads cost more.
Build Order: Reactor, 3 Supply Pads, Reactor
Upgrade Order: Warthog Gunner, Warthog Grenadier
Risks: If not done correctly this rush can be too slow to catch your enemy off guard.
Covenant Leader Rush:
Description: Again, all the units you need can be trained form your main base (the Prophet and the Brute Chieftan work best since they have better special units). If the base rally point is set on the grav lift, all newly trained units will instantly teleport to your leader. Send your leader with one or two special units to the enemy base then continuously train new units that will teleport strait to your leader and instantly get in the fight.
Build Order: Temple, 3 Warehouses
Upgrade Order: None
Risks: If your leader is killed before enough units can spawn on him the rush will likely fail.