Well before you start you should at least have done
2-3000 km this year so you dont damage your self after the upcoming hard work
then do intervalls (peridods of hard work), on flats. hills etc
also do practice sprints of say 100m or so. i practiced (before my crash ) 400 -500km per week though top pros practice 500 - 1000 when they get really serious (and good). the intervals will prepare you for the continuous effort of a TT.
Ps. I log all my rides and ride detail and speeds etc so i can see how i improve.
Some good advice, but don't worry about the distances covered as these may be inappropriate for you and lead to overtraining. During time trialing you ride at a steady pace for a duration of time, there are few sprints so there is no need to include too many sprints in your programme.
There are too things that make you go fast in a TT. A high aerobic capacity (VO2 max) and a high lactate threshold. The aerobic capacity describes how much work you can do aerobicly and to improve this do long steady distance work and 3 to 5 intervals of 3 to 4 minutes with a rest equal to the effort. To improve lactate threshold you should do temp rides of 20 to 40 minutes just below TT pace and longer intevals of 6 to 12 minutes at just above TT pace. The rest between the longer intervals can be much shorter, only 1 or 2 minutes. Do these long intervals until you have accumulated 30 minutes of quality effort.
You also need to think about pacing, aerodynamics and pedaling efficency. All of these make sure you make the best use of your energy. Remember (lots of people forget) all you have to do in time trialing is to propel yourself forward as fast as you can, nothing else matters!
All the training tips from 2lap are straight on! I can add...if you have aero bars or are going to get them, do not wait until your first race to try them.
I have found that stroke efficiency is the most important factor that you can control when competing in a TT. With staggered start times of 30-60 secs. as a beginner you should be mentally prepared to be passed or to panic if your split times seem to slow. Concentrate on keeping your pedaling even and smooooooth!...taking off and hammering will only cause your legs to give out too soon. You should have very little/no upper body movement when TTing..all your energy transfer is in your legs. Don't white knuckle your aero bars
And remember, if one muscle hurts, concentrate on using another, if you cramp, flex more in your stroke, but try to keep your cadence the same. A TT is a basically a mental game of how much pain you can endure...alone.