Read them, they have lots of good information that you will need to know. Go to the library also. Next, make a pilgrimage to R.E.I. and check out their camping section. I go into overload every time I visit them, but they are a good place to look at gear. Once again, I am not handing out endorsements.
Tents come in many styles and sizes.
One thing that you can count on is that the four man tent really only suites two or three people, size dependent naturally. A two man tent will do for one, etc. Unless you subscribe to the 'sardine can' approach, I suggest going for a higher body count tent because it's nice to have the room to stretch out in. If you can't, get a bigger tent. I like the pop-up dome tents personally.