First thing is first, setup and alignment. Normally I would talk about setup first but a lot of golfers out there struggle more with alignment than anything. When a student comes to me and is worried about the direction of the ball, my first question is where are you aiming. Sometimes, they look at me and go, “Straight!” ….. well what is straight. First you need to always pick a target. In this picture it is the red flag. Now, we need to setup the ball to go towards the red flag. I put down an orange stick in front of the ball to verify that the ball is going towards the flag. Now I can setup my body PARALLEL (orange stick on left) to the intended target line (orange stick on right). Thus making parallel lines, with the ball going towards the flag or some people like to say “Railroad Tracks”. Most students, end up aiming their body at the target therefore their ball will go to the right. When I am practicing this is what I do first to ensure I am setting up properly. I can either hit the ball (please make sure the orange stick on right is far enough in front of the ball that it won’t be hit) or I can pick up the orange stick on the right and just practice with the stick on the left for my body. After I practice my swing with the sticks, then I pick up the sticks and go through a pre-shot routine to practice aiming without and aid. Always practice with a stick or something on the ground if you are not going to go through your aiming process. This will allow you to hit balls and work on your stroke without having to think of too many things.
PS: If you are a left handed player, it is flipped!!