After taking skates off- remove guards, dry blades, then place dry terry cloth blade booties on blades. Never leave anything on the blades for over one hour. Wash your skate guards often. They accumulate dirt in the channel that can damage your blades. Check the screws in your blades often and tighten as needed.
Check blades periodically for nicks as well as sharpness.
Have blades sharpened as needed. A list of qualified local blade sharpeners is available on this site. When skates are not being worn, the blade booties should be on to protect the blades from nicks. Between skating seasons use WD-40 to lightly coat blades. Proper sharpening will maintain the correct rocker for the life of the blade.