Inspect your well head regularly. Is it clear of branches and debris?
Make sure your well head cap is at least 18" above the ground.
Regularly replace your filters if your system has filters.
Clear the ground around your well head regularly, especially after a storm.
Shovel snow away from your well head after heavy snowfall.
Have your water quality tested regularly by a professional testing company.
Use a company that specializes in well testing to have production, flow and stabilization tests performed.
Don't allow needles to gather around your well head.
Don't use home testing kits to check water quality - they return many unnecessary false positives.
Don't allow animal feces, chemicals or household items to be near your well head.
Don't ever open your well cap. That is for licensed professionals only.
Don't open the interior breaker box. Only licensed well professionals may legally open this box.
Don't leave a water source turned on if you go into dry-run (out of water). Turn off and allow well to replinish.
Don't assume your untested water is free of contaminants. Have it checked annually!