A moment to pass on things I have learnt in past year approaching TT and CX races. These are not best lines through corners/tyre pressures (Pete Hutchinson mystic musings) or secrets of aero (Jim Curry magic wind tunnel eye). More the other marginal gain things that have helped me, I hope they are of use.
1 Eat 3 to 4 hours before event
A bit empirical but it helps me. If I eat under 2 hours before I feel sick, if I have not eaten then I run out of energy. The optimal for me is the 3 to 4 hours before start time light meal. Not the full steak and chips stuff though.
2 Warm up
Getting older I find I need a bit more time to loose off, so at least 15 min gentle cycling. On CX this can be achieved by pre-riding the course to learn some lines without going flat out. Then some burst at race pace to get the HR up, say 1 min at intended speed, drop for a bit then 2 min, building up in intensity. Aim to get HR up into the race pace in steps. Good time to check bike is OK and practice some starts. Plan on warm up ending 10 min before start.
3 Have a plan
An objective of what you want to achieve. It can be as simple as a desired time, or working out how you will ride segments, a pacing target. Go off too quick and you run out of energy. But in CX races start too slow and you may be held up at bottle necks in track. For TT I found having a Power Meter and average speed display along with a thought on course and wind direction helps. e.g. an idea of the average power and speed I expect to hit for course, at Latton target power level and speed to Countrywide, pace and average power 1st time past gravel pit, then average speed at each roundabout. For CX time duration of race and HR, though to be honest HR is often just confirmation I am in correct zone and time is a gauge, along with lap board, to tell me when last lap is. If nothing else the plan makes you focus on what you want to achieve.
4 Training Plan
Sadly I have to report they work. I avoided having a structured training plan for a while, worrying it would take the fun out, make a hobby a chore etc. coming back from injury I have to say a training plan is effective. I did not follow it religiously, i.e I would move days around a bit, but followed the flow. One surprising benefit was I got easy riding days back. I would go out deciding it was a hard session and hit it, then on rest days catch up with friends who want to socially cycle or just go for a ride looking around. In the past I would try and blunder along at a given effort every time, neither stretching myself enough nor resting enough.
Plan in some rest time. If like me you are not a professional athlete or in the first flush of youth, work, family etc pull on your time and sometimes the fatigue load can hit you. Stavaistix is a Chrome plug in that provides hints on fresh you are or not. Training/riding works the legs, but it is when you rest they get stronger. Struggling to sleep at night with restless legs and a raised resting HR in morning, warning signs you are pushing too hard. Also have some electrolyte in the post event water bottle, it helps me reduce cramp as does some gentle cycling and stretches post event.