Since you are not just shaving hair, but skin cells, the blades should always be new (and there is no faster way to dull a razor blade than by shaving thick, unclipped hairs).
Handling the Razor
Once clipped, begin shaving your legs and arms. The most efficient way to shave is to practice a sawing motion, back and forth, against the grain of the hairs and then right back down with the grain. The up-stroke shaves the hairs, while the down-stroke cleans the razor off. The more traditional technique of rinsing the razor after each up-stroke is time-consuming and actually serves to dull the razor faster if you are rinsing it in warm water.
It is best to shave while sitting in a bathtub of warm water that you can constantly drain and refill; this way you stay warm and relaxed and avoid shivering, which results in tight muscles that can hinder your upcoming performance.
Also, keep in mind that shaving is a lot like yoga; it can be strenuous as you contort your body into different positions to get every stray hair on the behind your knees and on the small of your back. Try not to strain yourself in one position too long, for this can also have a negative effect on your race. When possible, have a partner shave those hard-to-reach areas (think of the possibilities, if that is your thing!).
As odd as this may sound, don't forget to shave the bottom of your feet and the palms of your hands. World-class swimmers swear by this method of heightening the sensation of these extremities, and you will notice a marked difference in your feel for the water. Fear not, there are no documented cases of thicker hairs growing back: All you are doing is removing dulled, less-sensitive cells from your hands and feet.
At the end of your shave, a lukewarm shower to refresh your body and some basic stretching can loosen up any tightened back or shoulder muscles.
Treating the Freshly-Shorn Skin
The final step is to dry off and splash your newly smooth skin with some rubbing alcohol. This serves two purposes: It opens up your pores and refreshes them even more than the menthol cream did, and it sterilizes any cuts or pores that could become host to painful ingrown hairs. If your skin looks scaly when dry, you can spread a light coat of baby oil over yourself for added moisture.
The best time to shave is generally the night before your race. Allow yourself at least 90 minutes to do the job completely, and avoid swimming until your warm-up the next morning. The sensation you feel with a new shave is short-lived as your newly exposed cells begin to dry up and die off, so you should avoid the water and save yourself for warm-up and the race itself.
Once the race is over, the sensation of a close shave will wear off within a week, but if you are competing again soon you can re-shave and it will still feel like your first time. A re-shave should also be done using new razors, but instead of going against the grain of your hairs, be sure to shave across the grain this time, left to right. This way you skim off the dead skin cells while not going over fresh hair stubble that, if aggravated by a razor, will cause ingrown hairs.
Because of the unique and short-lived sensation that a full-body shave provides, it's recommended that you only enjoy the process once a season, and no more than three times a year.
Often during a taper, swimmers feel unsettled and awkward in the water. By anticipating the super feeling a shave provides, you can rely on this pre-race ritual as the last step between feeling lousy and feeling great in the water. As such, the shave is as much a mental boost as a physical one.