Don't rub your eyes right after the surgery... That's all I can think of, since I didn't have it.

A whole lot of people that I know have had it and have been VERY happy with it though. It is affordable and comes out with excellent results almost every time. I would recommend you go to a good doctor (check his credentials, any papers he's written, etc.). Also, there are a few things you probably ought to be aware of:

There are a few issues with Lasik:
1. There is a very rare chance of reducing your eyesight permamently. This almost never happens, but it is possible. Similarly, you could get an infection, but these are also rare, especially so with Lasik (as opposed to some of the other eye surgeries).
2. The Lasik surgery is permament. It is possible to have minor corrections, but if it is seriously messed up the first time, or the shape of your eye later changes (both rather rare, but there still isn't much long-term empirical evidence), then you are stuck with the results.
3. There is a real chance that you could get Lasik and not have perfect vision. Some people still need corrective lenses even after the surgery. This is a possibility you should probably consider.
4. Lasik surgery cuts some of the nerves that tell your eye when it is dry. As a result, you may have dry eyes, possibly even needing eye drops, especially late at night or when you wake up in the morning.
5. Lasik reduces night vision in a significant portion of the people that undergo it. In addition, many people have a "halo effect" around any bright lights at night.

I hope that helps. As I said earlier, most people who have the surgery are very happy with the results.

-Biscuits