I've done it all kinds of ways. e.g. My set at PsyProject was largely pre-planned, but my set at Psybernetic recently wasn't at all. I didn't even know which track I was going to put on 1st before I opened my CD case.
Why pre-planned at PsyProject? 'Cos the construction of it was so complicated. There were a lot of different styles and sounds. If I'd got it wrong, it would have sounded terrible. Psybernetic was more of a journey, so easier to do.
I write notes and give scores on neat little bits of paper which go with the individual CD sleeves in the case. They can be very useful. Cheating? Nah, I don't think so 'cos it helps my performance, which can't be bad.
Hugs,
Barclay