Build SCV until you have 7
with the 7th SCV, build a supply
then build a barracks with the 8th
send 9th SCV to collect mineral
With 10th SCV build refinery- when this is done, put 3 SCV to get gas
Build a few SCV until barracks is done
When Barracks is done save up for factory and build one and get the add on
you should make 4-8 marines before your frist tank ends (remember to get the siege upgrade)
Once you get 1 tank send it to your enemy's base,(siege mode upgrade should be done while you are on the way)with the marines.
Siege mode the tank and kill anything that comes near it with the marines
This works well on 1:1 but never do it in 2vs2 or something like that
I tried it vs some 1100 + ladder people and i won. good luck:)

CreepColony's Opinion: Good strategy, but I think 2 tanks would be a lot better...one of everything always seems weak...1 lurker, 1 carrier, etc.