(Links to: Steps One, Two and Three)
It's time to take care of some logistics.
If you have non-paper exhibits you'll want to use (e.g. computer programs, tapes, DVDs, etc.) it's best to contact the court as early as possible to find out what they supply and what you'll need to bring with you. Find out how far in advance of trial you'll need to get them your specific request. If they have a tech person who will set it up, find out if you can have it set up the day before you intend to use it, so that you can run through it a few times with the tech person, including turning it off and starting it over again. Don't rely on the tech person who says, "I'll just leave it set up for you." If the power goes off or it gets unplugged, you'll want to know how to get it going on your own, and not be stuck waiting for tech support in the middle of your case.
Prep your witnesses, prep your witnesses, and prep your witnesses. Prepare them on where they'll sit, who they'll face, what you'll ask, what they'll say, what your adversary will ask, what they'll say, how they'll deal with objections, what they'll wear, what time they'll need to be there, what (if anything) they should bring with them, and how long they can expect the process to take. Practice, do a dress rehearsal, and ask one of your colleagues to play the part of your adversary, asking the toughest questions. Sometimes we end up finding a witness during trial, and rushing through their preparation - this is a mistake. Take enough time to prep your witness fully. Ask him if he has any concerns, anything he is afraid will come up, and how you'll handle it.
Expert witnesses could probably warrant their own post. But, briefly, in addition to the preparation you would give any other witness, there are also a few other things you will need to prepare. If you have an expert witness, you will probably need to turn over his resume or C.V. to your adversary, so find out exactly what rules apply and ask your witness to provide you with a copy. Review your witness's qualifications as an expert. Ask what publications they rely on in their work, whether the publications would support or controvert each part of his testimony. If your adversary is going to present an expert witness, ask your expert to review the other expert's qualifications and your cross-examination of that expert, if applicable.
Go through the case with your client. If you've made a trial outline, it is helpful when going through the case with your client. As much as possible, let him know when to expect, if and when he'll be expected to talk, and how he should behave. During the trial, you'll save valuable time if you don't have to lean over to your client constantly and explain every step of the way. Prepare your client for the most difficult parts of the trial - the prying eyes of the jurors; the prosecutor who points at him shouting "It was THIS MAN who..."; the graphic photos or damning evidence. If your client will be in jail during the trial, find out if he is allowed to wear regular clothing (rather than a jumpsuit), and whether he needs you to provide it. Find out whether your client will be able to have a pen and paper, and plan ahead to bring some extra supplies to keep him occupied (and not bugging you throughout the trial).
If your client is going to testify, the warning to prep your witnesses applies doubly, or perhaps even triply, to preparing your client to testify.
Make sure you have enough clean suits for at least the number of days the trial is expected to take, or make a trip to the dry cleaner.
Finally, the night before, you can pack up everything you need for your case. There is no excuse to forget something in the office that you might need for your trial. You need your case file, case law you might rely on in any arguments, books that you may need, blank notebooks and more pens than you'll ever need. I may go a little overboard, packing things like Advil in case of a sudden headache, cough drops, and lip balm. You're trying a case, not getting dropped off in the wilderness, after all, but I'm the type of person who can focus better knowing I'm prepared for anything (and, in most circumstances, I never use all of the things I brought anyway, but that's for the better.)
Get a good night's sleep, dress nice for the trial, wear your lucky underwear, get up early (but, let's face it, you weren't sleeping anyway), then leave for the office early to avoid any transportation snags (then, later, pace your office for a half-hour, imagining that you could have slept a half-hour later.)
Then, put on your game face and head to court.
I know I must be forgetting something... what is your last-minute trial prep?