I like to fast for a day before I take them, it tends to focus and involve oneself in the experience. But the truth is that any ritual will do, the more complex and consuming the ritual the better.
If you intend to be a real psyconaut, then do it right from the beginning. Note that Resinwhisperer has a ritual, eating pure good food for a few days. That probably won't make much of a difference, but his commiting himself by altering his behaivor in a way that he knows is healthy is a long step toward enlightenment.
My ritual is to clean my house top to bottom, even if I do not intend to be there. While I do that I am thinking about my excursion.
I fast for one day, morning to night, no solid food but again, that is my ritual. Then, if at all possible, I take my mushrooms (I just chew them up), lay out my cloths, comfortable, something that i feel good in and that makes me look good. And hop into the shower for a nice warm, relaxing wash. I don't like to be distracted by anything out of place.
By the time I get out of the shower I am usually just starting to trip.
Of course I have already put my music together if I am going to do that, put a few little snacks together, plenty of water, or some wine or a good couple of beers. I don't smoke anything when I trip but that is pretty much up to you, I wouldn't recommend smoking the first time.
I have a chant. I suggest you get one. It can be anything, lyrics to a song, a series of noises, a mantra. Own it, practice it when you are not high. You cannot use someone elses and you must never share yours.
If things should ever get hairy during a trip, your chant is your safety valve. It has saved many an experience for me andI highly recommend having one. Contrary to that relaxing song or tune, you can pull out your chant at any time anywhere you are.
Good luck.