If there is one thing that you can do to improve the consistency of your strokes, following the ball with the eyes is probably it. As an additional benefit, you'll find that your peripheral vision improves when you practice this technique. Tennis is a game that involves incredible bursts of speed. No matter how accomplished you are as a player, sooner or later you are going to have to scramble to strike a ball. Many times when players are in a match they sense that they are not moving well and are not getting to the ball quickly.
Big strides are really more counterproductive than helpful in most point situations.
When training players on my college team, I try to spend more time on sprints than on distance running. Tennis is a game of sprints. Whenever I have players sprint, I ask them to do so with little steps. If you train paying attention to shortening the length of your stride, you will without conscious effort find yourself taking little steps in a match. We all know that serve and volley oriented players are, by the very nature of their play, being aggressive.