Split steps are important. I can tell the difference in my level of play when I am doing a split step.
Trouble is, I have a choice. I can either think about doing a split step every time my opponent hits, or I can think about everything else. As things stand, I cannot do both.
How can I get the split step to be automatic? I have been trying to ingrain the split step for the last year, and still it only seems to happen when I make a conscious effort. And if I have to devote that much mental energy to the split step, there's no mental energy left for tactics, court awareness, ball awareness and stroke mechanics.
Anybody got a trick or a tip that might help?
The only way to make the split-step, and pretty much any other actions, "automatic" is to keep on doing it. I'm sure you've had to consciously think about your service motion at some point during your early Tennis career (assuming that you are comfortable with serving already). As you play more and more, your service motion should just be "automatic" and you end up thinking about what to do after you serve rather than worrying about your service mechanics.
However, there is one thing that I did do that helped me out with my split steps, maybe it'll work for you as well.
Try to keep a light jump, either with both feet or alternating from one foot to the other. If you watch the pros, they often do this when preparing to return a serve. First of all, this keeps your feet moving, and an already moving pair of feet are always quicker to react than a static one. Secondly, this motion helps loosen/relax your muscles and will greatly increase your reaction time. As you keep this jump going, just keep your eyes on the ball, AT ALL TIMES, and your body will react automatically, trying to chase down the ball wherever it may be.
Notice that I emphasize on keeping your eyes on the ball simply because sometimes, your mind will wander and even though you're staring in the direction of the ball, you're actually just staring at the blank space in the vicinity of the ball. That or maybe I'm just ******** and I'm the only person that does this =|