For lighting a match, it is ideal if the striker is on a firm surface.
If striker and box become wet, the striker will still work, but needs to dry first so that the surface is once again firm. Use a spare striker until then.
If match becomes we, just wipe dry before use.
Strike away from the body or in a downwards position. When striking the match sparks can fly off the igniting head. After using the match, run it in water to be certain that it will not light anything else on fire. Keep out of reach of small children.