For starters, most people are aware that you must replace a helmet after any crash where your head hit. The foam part of a helmet is made for one-time use, and after crushing once it is no longer as protective as it was, even if it still looks intact. Bear in mind that if the helmet did its job most people would tell you that they did not even hit their head, or did not hit their head that hard.

Leaving your bike outside for a day or two won’t do major damage. You may see signs of rust after a week of neglect. After one month in bad conditions, your beloved bike parts will start to degrade. The money you’ll spend having to replace corroded parts could have been spent on an easy storage solution such as a small-space gravity rack or a vertical hanging system.If all else fails, provide your bike with some shelter in the form of a tarp awning to prevent deterioration.

Be visible at all times. - Wear bright and visible clothes. Reflective stripes ads viability. Always stay out of blind zones. Alert other drivers before entering their blind zone.
Be predictable. - Others on the road must be able to predict your next move. Give proper signals before changing a lane or taking deviation.
Everyone in the road is dumb and partially blind. - Well, just imagine so and be prepared for an unexpected turn or braking.