It's the crossing of the forearms that put the punch in a golf shot. And it's the club going off the line that produces the majority of bad shots. If you feel that your hands are joined together and feel they are as one unit, you will be surprised at the amount of relaxation you'll attain.
The above are just a few of the main points you'll frequently hear when learning to become a good player, here's a few more; let the ball get in the way of the swing instead of making the ball the object. Don't try to pick the ball up -- the club is built for that purpose. Hitting behind the ball is caused by your weight being on the right foot. If the weight is forward it is impossible to hit behind the ball.
The reason for not going forward is tension -- keep the hands together, then the move forward is easy. Picture the shot as you would like to see it and keep your feet moving to the line of flight. Don't let them freeze to the ground. Conserve your energy when you play as you may need it before you finish 18 holes. Finishing the swing is very important. Without a good finish, to keep the ball straight is luck.
Out of bounds: The cause of the dreaded 'shank' is often debated however, one of the several possibilities is that it is caused by the club being on the outside of the ball. A good cure is to put two balls together two inches apart; if you can miss the outside ball, you won't hit a shank.