One training tool that has long been used in professional sports is visualization. In its minimal form, visualization is the act of creating a mental image of something you'd like to happen. Envisioning the task, such as a successfully completed football pass or arcing through a corner on the perfect line, can condition your mind and body to complete the act for real. Visualization and mental imagery is especially important for motorcycle riding, as many aspects are counterintuitive. Steering right to turn left, for example, or not chopping the throttle when the rear tire slides to avoid a highside. If you can "program" your mind to perform the correct action in a given situation, when you are confronted with that situation you'll be much better prepared to react properly rather than panic or make the incorrect, intuitive decision.
How do you visualize something? It's best to practice in a quiet environment, with no distractions and a clear mind. Yoga meditative practices are a great basis for visualization, and the freer your mind is of daily clutter the better your mental image will be. Start with something fairly simple, such as riding along a familiar straightaway. Try to picture in your mind as much as you can about the situation: Feel the wind on your body. Hear the engine. Note if the road or track is rough or smooth, what's on the side of the road and any distinguishing features. Add to the image as much as you can: What's the weather like? Are there other bikes or cars around? What gear is your bike in and how fast is the engine spinning?
It's worth pointing out here that visualization and reference points go hand in hand. The more reference points you have, the more complete your mental image will be. Ideally, on the racetrack you'll have enough reference points that at any given point you will have a marker in sight-if you don't, your imagery is discontinuous and you'll have trouble putting corners together in your mind. Even on the street, reference points help: A certain tree that tells you a decreasing-radius corner is coming up, or a mark on the road that reminds you of the driveway around the next corner.
Digging deeper into visualization, the next step is to picture going through a certain corner-again filling out the image with as much detail as you can. Once you've mastered the basics, you can try putting together a full lap of a racetrack, or a section of your favorite road. Now, the benefits of the process can be explored: Say you wanted to change the way you negotiated a certain turn, either using a different gear or moving your turn-in point. In your mind, you can visualize the change and how you would accomplish it. Run through the exercise several times until the imagery is smooth and continuous. The next time you're on the track you'll find it much easier to use the new gear or turn-in point, because you've already thought the process through and prepared your mind. Note here that the process has both physical and mental aspects: The act of physically changing gear, or how your attention should shift from braking to front tire traction at a different point in these examples.
On both street and track, you can take visualization to an extreme. Racers can envision a whole race in their mind, or visualize exactly how to deal with a certain opponent in a particular passing situation. A savvy street rider can plant an image of an entire stretch of road in his mind, with every turn stored in memory. A major benefit is that a panic situation can be avoided if you've prepared for it. If you've mentally run through the steps you'll take if a dog runs out in front of you or if the front tire suddenly loses traction in a turn, you'll almost naturally execute those steps rather than panic if the situation arises.

On the racetrack, you can...

On the racetrack, you can use visualization to practice a new line or apex marker in your head, a huge benefit when track time is sometimes limited.

When using visualization,...

When using visualization, the more imagery you can add to the situation, the better the results will be. When to start braking for a given corner, for example, or how hard to pull the lever.

Visualization can help on...

Visualization can help on the street just as much as on the track, by better preparing you for a panic situation or, just as on the racetrack, learning a given sequence of difficult corners.
Eventually, you'll want to work up to the most powerful use of visualization, changing an aspect of your riding with just one playback in your mind. Experienced riders can, for example, execute a change in line through a particular corner by just visualizing the scenario just once in their minds-often while still riding. The next time the corner is negotiated, the new line is taken without an interruption that can be distracting in the braking and turning thought processes.
Remember to start with simple images or situations, and gradually build up to something more complicated. Experiment with different environments, such as lying in bed at night or sitting in your favorite chair with some soft music playing-whatever works to calm your mind the best. With some practice you'll find the process gradually becomes easier, and you'll soon reap the benefits of visualization.