Any tips for TDI/Training first timers?

[DaveT]

Hi all - through an odd series of coincidences, I've suddenly found I'm able to attend Tactical Defense Institute (TDI) Handgun I-III classes this weekend. Very short notice, actually just got the handgun and haven't had a chance to even fire it yet.

I've plinked with handguns before, and try to practice good safety with firearms at all times, but I really expect to learn the right way to do the things I'm currently doing half right, and really get some good fundamentals going.

That said, I've never had any formal firearms training before (except for a 2-hour handgun safety course about 15 years ago). For those who've been to TDI or a similar intensive 3-day course, any tips for what to expect/bring other than the handgun, holster and ammo?
I've never fired more than probably 200 or so rounds in a day, and a lot of those would have been .22. I'm expecting I'll want/be grateful for a magazine loader. Any items to bring (directly gun-related or just general use items) that were really indispensable? Any other tips would be greatly appreciated.

Oh - and I'll be bringing a Springfield XD-9 (4-inch barrel).

Thanks in advance guys
Dave