Summarize:

Your hands should be roughly evenly spaced -- if the ball was a clock, your right hand would be at 3:00 and your left at 9:00. It can help to shift them back a bit, too, so your thumbs are almost touching in the back of the ball. This helps you get a bit more leverage on the throw. Throw-ins only occur when the whole ball completely passes over one of the touchlines. The restart occurs at the point it exited the field of play . The rules for throws are not super difficult, but you should be mindful of them with every throw. Even the pros sometimes make a mistake, but it is no less embarrassing when you do it in a game. A legal throw-in must have all of the following elements:  You are facing the field of play Both of your feet must be on or behind the touch line. As long as part of each foot is on some part of the 5 inch touchline or behind it and touching the ground at the moment the ball is thrown, the foot position is legal. You use two hands The ball comes from behind and over your head. You cannot score directly off a throw-in.
Pick up the ball with both hands, one on each side of the ball. Review the rules to ensure perfect, legal throw-ins.