To determine who goes first, put all the tiles into the bag and mix them up. Each player chooses one tile, and the person with the letter closest to A or a blank tile goes first. Play continues in a clockwise direction.
Next, put all the tiles into the bag. Each player draws seven tiles and assembles them on their rack. Player one takes two or more tiles and lays down a word either across or down, with one letter on the star in the center of the board. He counts up her score, announces it and draws tiles until he has seven on his rack again.
The second player lays down at least one tile adjacent to a letter on the board to create a new word or words. This can be as simple as adding a prefix, suffix or plural to the original word, or it can be a totally new word. Again, the word must read either across or down, because diagonals aren't allowed in Scrabble. The player counts up his point total, announces it, and the next player continues the game, building off of any word on the board. If you use all seven of your tiles, you get a 50-point bonus, which is called a bingo.
When you use a blank tile, announce what letter it will represent. It will remain that letter for the rest of the game. Blank tiles aren't worth any points.
Scattered around the board are bonus squares indicating extra point-earning opportunities, either premium letter squares or premium word squares. The star in the center is a double word score. A bonus square can be used only once per game.
Any word can be challenged, and this is where your dictionary comes in. You may use the dictionary only to look up a challenged word. If the challenge is successful, the player takes back his tiles and loses his turn. If the word does exist, the challenger loses his next turn. A player may only challenge a word directly after it's played.
The game continues until one player uses all of his tiles and there aren't any in the pouch, or if there are no more tiles and no one can make a word. Add up the total of your unplayed tiles and deduct it from your score. If you've used all of your tiles, add the total of the unplayed tiles to your score. The winner has the most points.