I always play for points, but as the board fills with words the game’s optimal strategy evolves. The first play, of course, can only be a single word (doubled, of course). But the next play does not have to be at right angles to the first word. So I try – when I can – to play long and interesting words that run parallel to others already on the board, so that I can pick up the points for my own word, and a series of two-letter (or more!) words that are created by the juxtaposition. I also go for bridge words that might add an “S” to an existing word, then as my word progresses it might add a “D” or another “S” to another word (for example, JOIN can become ENJOINS, with the E and the S parts of other words), so I get points for three words – or more.
Late in the game, when the object is to run out of tiles first – and the easy words and chances are all gone because of the letters so closely packed that no new long words can be easily formed, then it’s time to go for the simple (and sometimes very lucrative) two-letter combinations that can eat up one’s last remaining tiles, make the board harder for the opponent to play onto, and cause her (it’s usually a “her” with me: either my daughter or my sister, at Thanksgiving, after the pie) to have to skip a turn.