You have to square up (like you do in a real life situation) to pick jump balls, User Picks are all about timing and knowing the routes being ran. If the ball is hanging in the air you're going to have to square up using the strafe feature and go up and grab it or bat it down. If the ball and the receiver are moving you have to time it right and get in the area of the ball (red circle)
Same with Swatting the ball down just more timing involved....