build 8 scvs
on your 8th scv build a depot
on your 10th scv a barracks
on your 11th scv another barracks
continue building scvs non stop
while building the two barracks when u got 100min make a refinery
when first barracks is done make 1marine only! and continue making scvs
when u got 150min make an academy
when the secound barracks is done make a secound marine! so out of 18guys 16 should be scvs and 2marines
now make a depot and a 3rd barracks
u should have 2scvs mining gas
when depot is done make another and keep making scvs
and start making marines,firebats, medics i like firebats cuz they kill zealots early on and lings but you got to get a sizeable force in under 8min

CreepColony's Opinion: If you can, try to get tanks because they will really help.