Wellcome to the forums. Kinda hard to put several hundred hours of trial and error into one post but here is something to begin with
In general:
- Expand as fast as you can.
- When you think you have enough research, double it
- Maintanance can kill you. When a ship is obsolete; upgrade or scrap it.
- Train all your ships/fleets.
- Watch your empires happiness.
- Don't forget first level of cloacking (stealth armor) is damn cheap to research (both for you and your enemies).
+ + + +
For a start, check out
this thread on fast expansion
Have fun