Try to avoid gaps in your rows; fill them in completely.

Keep an eye on the preview box to see what shape is coming next.

Try to leave places where each type of shape can be placed without creating a "hole" in your wall. For example, try to make sure you always leave a ""flat"" area at least two columns wide, to make a safe landing place for the two-by-two shape.

Since you get more points for removing multiple rows at a time, try to fill in only nine rows, leaving a narrow gap that you can fill in with the long, narrow shape (the one-by-four shape). This is the only way to remove four rows with one shape, which is your best scoring opportunity. Of course, this is a high-risk strategy, and is best-employed early in the game when the speed of the shapes is still pretty slow!

Since shapes drop from the center of the playing area, try to fill up the left and right sides during times when everything is under control, so that if you get into a crunch, you won't need as many keystrokes to get a given shape into its proper spot.

Don't waste time rotating the two-by-two shape.

If you drop a shape in the wrong spot, or turn the wrong way, DON'T PANIC! Keep your head about you, and you have a good chance of recovering.

Try playing the "debris" variation. In addition to being an interesting variation of the game, it will also help you learn how to deal with buried holes in your wall, and therefore train you on how to recover from mistakes.