In a purely watt per dollar equation, TT helmets constitute practically the best bang for your buck. Alas, I am not going to bore you with a TT helmet review, but I would like to take a minute to point out one (embarrassing) user error that is more common than one would expect.
Exposed cable housing is actually a fairly large source of drag on the bike. Keeping your cables out of the wind can be highly advantageous. These days, all reputable TT bike frame manufacturers put a large emphasis on routing cables inside the frame.
There are volumes of information out in print and cyberspace about training for time trials. Loads and loads of information about how to prepare the engine. Specific intervals and workouts, etc… In this era of power meters and ultra-refined nutrition, it is easy to forget the broader picture and goals.