Always keep your lenses clean, perhaps using a solution and cleaning cloth. One such solution is called Solution 30 which is produced by Carl Zeiss. A clean before each photo shoot is advisable.
It is probably a good idea to fit a UV filter to your lenses. If kept permanently affixed they may help to protect your valuable lenses from damage. Clean this filter to. Sometimes, when photographing bright lights, it might be best to remove this UV filter.
Spots can still appear on your lenses by way of dust or water spray et cetera. In these cases spots will appear on all your photographs in exactly the same place. If you use software to remove/disguise these spots it can save a lot of time selecting all these pictures before you edit one of them. Once your edit is carried out, because you have selected all the pictures, those spots will be removed from all your photographs.