Glare and sunstrike
Glare and sunstrike can severely reduce your vision and be disorientating. A clean, scratch-free tinted visor can reduce glare a little but good quality optical sunglasses, particularly polarized, are better. Photochromatic glasses are good too, provided the sunlight isn't too strong and there arent a lot of shadows (they take a few seconds to adjust to different light levels). If a sudden blast of sunstrike hits you, try angling your head down so that the top edge of the aperture you look through covers the sun, and look out from under (its effectively like a sun visor in a car).
Be aware that other road users will be suffering from sunstrike too and may not see you. If you are casting a long shadow directly in front of you be aware that you may be completely invisible to traffic ahead. This is a particular problem if you are travelling westbound in the morning or eastbound in the evening.
Never wear a dark visor or sunglasses. Keep your headlight glass and helmet visor clean, and free of scratches. Use main beam whenever the road ahead is clear, look for lights ahead and dip before you see the oncoming vehicles headlights.When an oncoming vehicles lights shine right at you, look along the left of the carriageway (lines, reflectors, kerbing) until you can see past the vehicle without being dazzled. Slow down if necessary.Most modern bikes have twin headlights and twin taillight bulbs. Check your lights work before every ride and ensure the headlight is adjusted to suit the load being carried. If you only have one headlight and a bulb fails, it's probably the more-used low-beam. Switch immediately to high beam, stop and aim the headlight lower to compensate.Use the roadside reflectors and white lines to build a picture of where the road goes, similar to the vanishing point. Your real vanishing point, however, will be closer - only as far as your lights let you see. Right side markers usually have two amber reflectors, left side markers have a single, longer silver reflector. When these reflectors intersect to your left or right ahead, youre approaching a bend.