Skateboarding ollie problem?

okay so basicaly in an ollie you wanna slide your foot up that makes the ollie but if you suck your knees in youll go higher while your in the air watch the board if it looks like its going down or its moving slam your feet down. its also a good idea to make sure that your leaning forward over the board that will make it stay under you. in terms of spinning make sure to keep your back foot planted so that it doesnt spin the board. the only thing it should do is push down to make the board pop