I'm a bit concerned that you are asking what you might need to do, which to me hints that maybe you're not completely ready for CBT tonight. However, if you genuinely feel like you are ready, I would say it's up to you. If you have friends and family, do you have parting words you feel they should know since you won't be able to speak to them again? I don't know about you, but if I had a solid plan for my own CTB (not yet), I would probably dress up or something. It all depends on if that is meaningful to you. Perhaps wearing your favorite clothes or something comfortable, maybe something you've always wanted to wear, etc.
If you don't mind me asking, what is your method?