For street riding I do not go through specific preparation, other than wearing the minimum safety gear (boots, gloves, helmet, back protector and leather jacket) and ensuring that bike is well maintained.
I use my street bike mostly for commuting to work, so I don't often spend more than 1/2 hour in the saddle.
For track riding, which is where I try to spend as much time as possible, I am very anal about the bike preparation. I try to maintain my track bike in as near to perfect condition as possible.
The last thing I want is to run in a mechanical issue when I am riding at +160 mph...
For my physical preparation I do a lot of running all year round (30-40 miles/week) at a "competitive" pace and I find it allows me to keep very "fresh" on the bike, even at the end of a long day of open track riding. Sleeping enough is also very important (as much for running as for riding) before going to the track and also at the track when I do multiple days sessions. (sometime up to 4 days in a row).
I also like to visualize the track and go through each corner in my head multiple times (while I drive to the track and also in between each session).
Of course I also like to read over and over again the twist of the wrist books to remind me of the things I need to work on to be faster.
I have only raced once, but I found it to be so exciting! I did not expect it to be so much fun!