How do you come up with your rocket design?

[Pecan]

Shouldn't this be merged with How do you design?

[morph113]

For me I decide everything by eye and KSP experience. I don't use any mods like mechjeb. If I build a completely new design and do a mission i haven't tried before, then I go by judging myself how big my travel stage is or looks like and how much thrust and fuel I would need to reach a certain target and return safely back. Usually I end up with more fuel than I actually needed though. You will get the hang of it after a while eventually, allways knowing which engines to use and how much fuel you need. If I need to lift something really heavy, then a good choice is with one or more inner tanks sourrounded by detachable boosters, heavy boosters, big boosters, many boosters. You want to get that heavy thing off the ground and as high as possible as quickly as possible.