What do the icons indicate?

Arrows crossed in an X=rotate the letters in the circle, costs 5 coins

Bulleye=one letter revealed in a location you pick, costs 200 coins

Lightbulb=one letter revealed in a location the game picks (almost always the upper most word on the left side, and then it works it's way down and to the right), costs 100 coins

Rocket=5 letters revealed in random locations the game picks (and sometimes that is multiple letters in a single word), costs 300 coins