Interplanetary Fuel Usage?

[Cooly568]

I can't seem to build a rocket with enough fuel/power to get out of kerbin's SOI and end up having to use the lander for the transfer.

What am I doing wrong?

If someone has a working interplanetary lander design may you please share it?

[trbinsc]

Try putting a less powerful engine on your transfer stage.

[djnekkid]

You need moar boosters

But joke aside... This craft (stock+mechjeb+isa map sat) took me to Duna with LOTS AND LOTS AND LOTS of fuel to spare... (Just in orbit for now tho)

Even the core 2meter stage were even almost full when a 155km orbit were circulized. About a tank were spent, and 3 were left.