First of all, know your two-letter words. There are 96. These will give you more points than you think.
Also, know your three-letter words. There are a lot of these, about 972 of them, so you might not want to try to memorize them all right away. Try to memorize those that will provide you with a way to get rid of weird letters like z or q. Eventually, though, it's important to have them all memorized. You probably already know more than you realize.
Also, keep in mind common letter groupings to help you look for BINGO's (using all seven tiles in one play). For example, look for suffixes like ER, ING, EST, OUS, TION, etc., or prefixes like BR, UN, IN, STR, SCH, SH, CH, etc. You will find that there are already a lot of 7- and 8-letter words you are familiar with.
One other list that is important is the U-less Q words.
