also what do thruster blocks do ?
I've built a stable rocket but it only gets me to 30000 ft or whatever. Has anyone got tips for building a safe rocket which can fly?
Firstly experimentation + patients are absolutly a must!

Too me 3 days of playing to achieve 30K, an 1 Month to achieve stable orbit!

So dont expect too conquor the solar system over night!
By definition I am a purist, absolutly never install mods, but there is some very good ones too download, been developed.
Please check the forums, if you already haven't @
http://kerbalspaceprogram.com/forum/index.php Register + Say HI.
Most of the fun of KSP, is develping your own craft, an experimenting with different designs!
One rule of thumb, more parts = more weight, so smaller can be better!

An event with a super computer 500+ parts will kill most PC's!
Too Describe a solution too your building dilema:
Command pod + Parachute - on top!
Radial decoupler - under CP!
ASAS - under Decoupler
4x Tanks of Fuel - under ASAS in a line!
1x Biggest engine, LV-30!
That will easily achieve 100KM's Stabile orbit.. If you can pilot it!

Hope to see your results, an Kerbals voyages!