Since I seem to get a lot of search requests for it, here’s my official Bejeweled Strategy Guide:

1. Always play on Level 2. It’s impossible to get a decent score on Level 1, and Level 3 is just too darn fast.
2. Getting a high score is less about making single matches and more about making combination moves. Always go for the combo-setup as opposed to the easy score.
3. Make vertical matches whenever possible. This allows for more pieces to fall and gives more opportunities for combo-scores. Matching a horizontal row means that the three rows fall together, and your chances of making another match are smaller.
4. Try working in only one area of the screen at a time, as opposed to jumping all over the place. I find I do better when I concentrate on a smaller area and get every possible match before moving on.
5. The time of day that you play can have a huge impact. If I play in the morning or after lunch when I’m “fresh”, my scores are much higher than when I play at the end of the day (with my brain fried from ten hours of work). Find the time that’s best for you.

I have to warn you though, my personal strategy seems to have a built-in score cap. While I have occasionally broken 10,000 points, 9 times out of 10 my score will hover in the 7000-9000 range. If that’s an improvement for you, go for it.