General strategy that almost always works:
1. Build up planets
2. Build ships
3. Do research
4. Shoot enemy

The specifics may vary depending on your playstyle and what your enemy is doing.

Let me point out from experience, that biulding an end game fleet while just defending and letting your opponets do whatever they want, will result in a loss.

Good strategy concerning TEC? It's pretty simple.

In the game lobby, go and click on the TEC icon. Either click once, twice, or three times. You will either get the "change to Vasari upgrade", the "Change to Advent upgrade", or the "Change to Random Race upgrade", a 66% chance of getting a better race than TEC.   

In all seriousness though, TEC is god awful. They have the worst early game economy and frankly need a huge buff to be on the same page as Advent and Vasari. The fix may be coming in 1.1, but it doesn't look like it is.

You have to out macro and out wit your opponent with TEC. The big advantage of TEC is they have some of the more creative/strategic abilities in the game. The scouts have the bomb ability. The Hoshiko has the demolition bots ability. The +25% damage, soon to be +40% bonus on the Cielo is a great late game tech. No enemy cap is safe.

Although they are the simplest race, TEC takes a very experienced veteran to have a prayer against an Illum spam or an Assailant spam.

To quote that, I actually use that sometimes. Attack from multiple planets simultaneously to confuse players so I can take their planets and smash their fleets while in turmoil. Once it's over, I do it again until I win.

It's a very good strategy over LAN and ICO.