Start Small, Aim Big
Most players want the most points possible each turn, but forethought can go a long way to winning the game. Don't be afraid to play a small word, like "bee," "go," or "red," if you can keep high-scoring tiles that can be used more effectively later. Don't think only about the current move, but about future moves, too.
Trade In Your Tiles
One of the most under-used aspect of the game is tile exchange. Most novice players don't even know that you can trade in tiles at the start of your turn. If after several rounds you can't make any plays, consider turning in your tiles for new ones.
Look For Easy Ways to Increase Your Score
On each Scrabble board, there are colored squares that will increase a player's score if he plays tiles on it. These are frequently "double word" and "double letter" squares in blue and red. Always consider if your play can take advantage of these instead of opting to play the titles somewhere else.
Build On
Once a player places a word on the board, other players can build upon the original word. For example, if someone played "side," another player could put down "sea" next to it and create "seaside." This is a useful and crucial part of the game because when a player builds like this, he receives points from all the tiles in the new word. For example, creating "seaside" would provide a higher score than just placing "sea."
Know the "House Rules"
The official Scrabble rules are fairly strict: no proper nouns, only English words, no brands. But often players bend rules and change them. Ask your opponents about any "house rules" before starting to play. You may be able to play words like "Pepsi" or "ciao," if the host or game owner plays that way.
Sit Down With the Dictionary
This sounds simple, but in practice, few people crack open the dictionary and start memorizing words. With an increased vocabulary, Scrabble players will be able to make words from their tiles with less difficulty. So with words like "miasma" and "myriad," players can get a head start on opponents.