do missions...
1. get some cash:
a) exploring and keeping only planets above 800 land (or 900 if you prefer, i`ll recommend 800 if you have little patience), when you have 5, you cluster them all together into a c1, making it a big fat c1.
then, decide on what type of income you want, agriculture, industry, tax (housing), commercial or mining (for miners only, unless for some weird reason you want to spend your whole life strip mining).
if you`ve decided on housing, only research housing, if it`s anything else, research 7 in housing, then start on whatever you`ve chosen (this has been proven as the most efficient way to go for research)
then once you`ve got your fat planets, build the infrastructure on them to earn money,and if you`re agriculture / industry / mining, you have to sell your stuff on the market in order to earn money.
b) strip mine: basically just explore for planets and mine all the ore off them, then sell the ore on the market
c) enslaving (wait till you finish researching your ships first and it`s generally not too easy to earn much from this)
*of course to start with, just keep whatever planets with 300+ land that you have so you get a bit of income first to maintain the upkeep for your scouts.
2. research all your ships
this is pretty self-explanatory
3. you think of what you want to do next