1. Most helmets have the brand name on the front.
2. Some helmets have a sticker inside saying "Front." Very helpful if yours is one of them.
3. Virtually all helmets have the nape straps anchored at the rear. So the rear will be the end where two straps come almost together at the rim, or even join at the rim. When the helmet is correctly on your head with the front end forward, the furthest forward strap should come just in front of your ear and almost straight up to the helmet. If you have
a strap coming around the side and angling forward across your cheek, you probably have the helmet on backwards.
4. If your helmet has a stabilizer, that is the rear. All helmet stabilizers are designed to be used on the rear.
5. The elongated "aero" style helmets are all made with the longer part toward the rear.