For those who aren't regular Tetris players I have a tip that might help you score more points.

By dropping a block quickly using the enter key you gain more points
You can hit the return key for the block to drop automatically, but make sure you have the block lined up correctly as you cannot stop the block falling once the enter key has been pressed.

Try stacking blocks up to make four rows disappear at once. Leaving a gap for one straight red four block to drop into is the only way to do this. Doing so gives you much higher scores than removing four rows individually.