Time trials are one of the least popular forms of racing here locally. The size of the fields are a touch smaller than cross racing. Most people who focus on it often are either triathletes (or used to be), or simply have a innate attraction to the "race of truth". When it comes to omniums and stage races, it can be a crucial element of overall placing. So, how do you get better at TTs?
There's is a lot to say about each specific aspect of racing TTs, but I think in general there are three areas that make the biggest difference in whether or not you can be competitive in time trials: aero equipment, mental strength, and training.
1. AERO EQUIPMENT
When I first started getting interested in time trials a few years back, I got some advice from a guy on the team who'd done well with time trials. Something he said stuck out to me: "it's a weapons race." I've found this to be true. While you can't pay for creating power, you can pay to keep elements from slowing you down.
Cycling Tips has a great article about what saves you how much time vs cost so you can figure out the most bang for your buck. Here's my list of essentials and around how much time it'll cut off your time for a 20km or so TT (pretty close to the standard 10-mile TT we do around here).
60sec - TT Bike/Aerobars and adjusted seat position (i.e. aero bike position)
10sec - Aero Bike Frame
30sec - Deep dish wheels
30sec - Aero Helmet
15sec - Skinsuit
10sec - Shoe Covers
So, in theory, you should be able to shave off at least 2 minutes of your time just by using the correct equipment. That usually the difference between 1st and 6th place or so. So, pretty big.
2. MENTAL STRENGTH
Every cycling discipline has it's own sort of mental strength needed for success. In a crit you have to have quick tactical thinking and be able to ignite your body in a one-on-one contest for the line.
Mental strength for success in time trials largely depends on self motivation and ability to stay focused for long periods. You have to remain focused the entire time trial in order to keep your body right at the edge, as well as make sure you are staying in the most aero position. You have to avoid letting your mind wander and keep yourself on task.
You also have to push yourself to the limit without having a direct competitor. Since there's no wheel that you're trying to hold onto, you have to motivate yourself. The biggest enemy to this is your body giving you messages to back off or give up. I have three things I'll do to keep myself going hard when it gets hard towards the end of a TT:
A) I read an interview with a pro and she said in time trials when things start getting really hard she tells herself "strong mind, strong body." Since then I've repeated that phrase to myself when the going gets tough.
B) I think about all the hours I spent on the trainer to prepare for this short 20 minutes, and that I can't let it all go to waste.
C) I think that my competition is currently only a few seconds ahead of me, and I have to push harder to beat them, and if I don't I will lose by only 5-10 seconds (those sorts of time gaps are quite common).
Assuming you're already training for racing and that you have a high level of fitness, I think it's important to do workouts that mimic the duration and intensity of the TTs you plan to race. If the TT will take you about 20mins, do 20min efforts on the trainer. This is also a good opportunity to train mentally for what your mind will do at the end of these sorts of efforts.
Also, I think training on the bike you're going to race in the position you're going to race in is important. The position is a bit different and you use slightly different muscles than on a road bike. The more you train in that position the more comfortable it is. You will also be working the muscles you'll need specific to that position and they will get stronger. The more comfortable you are and the stronger those specific muscles are, the more power you will be able to generate.
So, I think those are the three biggest things to getting good time trial results!