Letterpress is a fun new word game that was released a few days ago for iOS. Each game is relatively short, usually 20 moves or less. In the short time it's been available, I've played about a dozen games and have won more than lost. Here are some basic strategies I've come up with while playing.
The game themes seem centered around influence and defense so consider each move in light of those two themes.
1) Start on the edge of the board and push towards the center.
2) If an opponent plays a word, try to play a variation on that word, you'll take the initiative on those letters.
3) Prefer longer words to shorter words. If you can't find a word longer than 5 letters, take a break and try later. There's no time limit.
4) A shorter word is preferable if it uses more of your opponent's letters.
5) Check every potential word choice to see if it can be easily turned into a longer word. If it can, then play the longer form instead.
5) Prefer words that build defenses around your letters. Remember, the score matters.
6) If your opponent has a clear border with you, attack it. This will result in building more defensive letters for you and slowly squeeze out your opponent.
One strategy Loren noted in his recent interview on Letterpress is that the edges are easier to defend. Also, he noted that if you are stuck with a Q and no U, you'll always have an I, so play QI to end the game on a high note.
Something fun I noticed: Did you know you can rearrange the letters on your in-progress word? Play around with the string of letters: drag individual letters, move letters back down to the board, move other letters into their place. I like to start with a word and then morph it into other words.