You shouldn't just remove a lot of space because someone you know told you it would be better to do so. Most come to understand why people leave out a ton of space in the middle when they reach a certain level in melee. It is because it makes the game a huge game of tug of war. And that's not fun, especially when it comes to siege tanks.
If, and If you were not experienced at melee, you would probably be thinking- well if siege tanks, why not just go aerial and whoop their asses?
Here's problem #1: Aerial units are high tech, which means getting them will take a longer time than the opponent can with ground units. When you are late, you don't want to be late because most of the times, you get your ass whooped before you can get aerial units.
Here's problem #2: Aerial units are weak. They get their asses whooped every time, and are only used because they can strike at areas ground units cannot. They quickly lose their advantage once scouted, and they cost a ton.
Here's problem #3: The highest level of air unit is pretty good, Carriers, BCs. Well, if you knew how long they take to make, you wouldn't bother going for them before you own the game with your own ground units. They're partly 'lulz' unit for turtles and newbies.
Also, your natural mineral is tankable, by all means- that is not good. You don't want any of your mains or natural to be tankable.
Thats two huge advantage for T already.
By all means, you should first study the basic 3 strategies of each race.
T - 2 rack, 1 rack double, 1 fact double.
P - 2 gate, 1 gate double, 2 gate core
Z - 12 hatch, 12 pool, 3 hatch
It's probably all on TeamLiquid or something.
You should also study some pro maps too, since you seem to have no idea what you're doing.
Heres some:
4p: Luna, Python, Othello
3p: Tau Cross, Longinus, Rush Hour II
2p: Peaks of Baekdu (or something, it sounds similar), Blue Storm
Download it from www.iccup.com
None.