Pre-shot routines are a part of the golf game that very few people teach or talk about. This is because a pre-shot routine is not directly related to the golf swing and does not deal with mechanics, course management, etc. I feel that finding your own pre-shot routine that works best for you and allows you to be as comfortable and confident as possible before a golf shot is very important.
A pre-shot routine is something that is unique to each individual. The best pre-shot routines involve some degree of visualization, practice swings and alignment adjustments. Visualization is important because you want to have a plan or a blueprint for exactly how you want your shot to go. It is important to have a plan for each shot and take into account exactly where you want your ball to end up. It is also important to find hazards that may be in your way and where the best place to miss a shot would be. Better players do their visualization when standing behind the ball so that they can imagine their ball flying toward the target. Practice swings are important because they help you get loose and rehearse the feeling you want when you actually hit the ball. Practice swings can be unique to you, some players take full swings at 100% normal speed and some players make very small swings that just rehearse impact. Alignment adjustments are a key to getting comfortable over the ball. These come after you have addressed the ball and are trying to make sure your body and clubhead are aligned at your target. Usually these adjustments involve adjusting your feet or hands to become comfortable before you pull the trigger.
I will use my pre-shot routine as an example. After I have figured out my yardage, lie situation, club, shot shape, etc. I will go beside the ball and take two small practice swings. My practice swings are slow and I only take them back about ¾ of the way to the top and I rehearse what I am going to do with the club at impact. This helps me get a feel for hitting my desired shot shape such as a draw, fade, high shot, low shot, etc. I then walk back about five feet behind the ball and visualize my shot. After that, I walk beside the ball and take my address position and adjust my feet, body and hands until I am comfortable and aiming correctly. While I am adjusting myself I will look back and for the between the ball and my target until I am all set to go and then I pull the trigger.
This sequence of motions is what works best for me and it has taken me a long time to find what gets me the most comfortable over the ball. Every pre-shot routine is different and you may have to do some experimenting next time you are out on the course to find the one that works best for you.