Pass Up Your Turn
If you're willing to take a gamble that might pay off big, then this strategy's for you. Rather than making an obvious play, indiscriminately plunking down a couple tiles for just a few paltry points, survey the situation.
As you study the board, first look for multiple ways to play your tiles, adding the points up and mentally comparing the scores. If you're not impressed with the outcomes, take a closer look at how your opponent's been playing. What's her next likely move? Has she already created open-ended words that you could tack a few tiles onto to spell a high-scoring word? Or would you benefit by holding onto your existing tiles until your opponent has taken another turn, potentially opening new opportunities for play on the board?
If you answer yes to that last question, then you may want to sit out for a turn. Passing on your turn -- and wasting nary a letter -- makes sense if you're waiting for an opportunity to pull big numbers by using the tiles in your rack more strategically [source: Lawrence].