Ride Designing

A little question, how do people design their rides, do you theme as you are building or build the complete ride then theme it.

I only ask because i know someone who does the former, and he gets some very gd designs, and as i have just got back i hope to improve my standard, and wonder whether it would be a good idea to change style.

I usually theme it when I complete it.

I first build it and do the landscape for it, then I theme it.

I used to build it then theme it however i liked, but i cant really now a days because i dont have it on my computer anymore and i dunno where the disk is[:(!]