- Showering close to the time you're going out (unless it's very cold) is a good idea, although generally I don't bother as I'm scum. But when I do, I feel better for it.
- The shaving thing depends entirely on your look. I've had it said I look both better shaven and unshaven so I don't know. Last time I went clubbing without shaving for a couple of days a couple of people thought I was trying to grow some dodgy taché so I tend to do so a few hours before going out (not right before as that get's in the way of make-up plans and/or if you cut yourself you'll look like a fool*)
- I always try to sleep during the day (again, as late as possible) before clubbing so I can last till the club closes at 7:30am, otherwise I just crash (unless I'm on drugs) at 3am.
- I would also include making sure you have some sort of hangover cure / rehydration "kit" ready for when you get home and/or comedown remedies. You'll be tired when you get home, you cba to look for your Vitamin tablets or whatever.
- Always try to make sure you have chewing gum on you and don't rely on buying it while out.
- Have a bottle of vodka in the house at all times so you can get drunk before going out (cheapskate++).
There are probably others.
The honesty thing sounds a stupid idea, unless you're convinced she fancies you, in which case you may as well be flippant.
* = I realise the juxtaposition of mentioning this in the same breadth as wearing make-up is hilarious, **** you.