There are walk throughs around here somewhere, but basically as bladevenom stated, colony ruah.
First - buy a colony or buy a factory .. this depends
Second turn - buy colony...
Use up your money if you have to and buy and send the colonies out.
Dont worry about warships or anything in the initial phase, just rush and grab as many planets as you can.
Planet setup, diversify initially... in other words have at lease one of each on your planets then as you expand, find some good quality planets and specialize.
I suggest you read up on some of the articles on economy in the forums, that will explain alot on how the game works.
The way I see it, controlling the economy is key in the game.