Here’s a couple of top tips I had a wee while back from Lee Cunningham when he coached me in the early days:
 Always wear a fireproof balaclava when wearing a helmet. Not for the reasons of fire precaution but to keep the inside of your helmet from getting dirty quickly, especially if you wear hair gel, wax or similar.
 After each track session, whether the weather is dry or wet, place the helmet safely on the bonnet of the car. The heat from the engine will dry any perspiration if a hot day and dampness if a wet day. Of course, place safely as you don’t want to drop the helmet on the floor.
On an aside, scrutineers don’t like dark visors as if in an incident, the marshalls or paramedics cannot see your eyes. You can choose a darker ‘Light Smoke’ shade of visor as seen on this Arai GP-6 than the standard clear, but not ‘Dark Smoke’ for sunny days. Personally I also like to have one of these long stickers which keeps the sun out of my eyes and one other tip for duller days is perhaps the option of a yellow visor, which I have used too.