I hear often claims similar to "many cyclists wear their helmets the wrong way" and "wearing a helmet incorrectly significantly reduces it's protective ability".
My helmet is similar to the following one(only with vent holes). Note the two-stage straps on both sides (that is, one can tighten the helmet forward-up and backwards-up).
The manual featured a couple of crossed out pictures - don't tilt the helmet over your eyes (duh!) and don't tilt it so far back, that the forehead is bare.
I am in doubt if I am using my helmet correctly. What are the checkpoints to cover, before being positive that the helmet is not providing just a false sense of security?
For example, tightening. How tight should the helmet be? Must it resist grabbing it by hand and forcing it sideways around my head?
Another question of particular interest to me concerns the rear straps. Those seem to either hang (very) loose, or, if I tighten them and when I tilt my head (slightly) forward, stretch out and limit the movement (in an uncomfortable way).