Yeah, meditating before tripping is always a good thing. I also like to stretch before hand to help loosen up the body so energy can flow through it easier. And if you have trouble relaxing smoke a bunch of weed.
You should also clearly state out loud to yourself what it is that your looking to gain out of the experience that night/day, whether it be spiritual enlightenment, a fresh start, or to just have a good time.
Also, dont forget not to give into astonishment. When I first started tripping I was so busy looking at how amazing everything was that I didnt get anywhere, and before I knew it the trip was over.