Trying other strains can help but this is just a natural process of your body building up tolerance to cannabis, just like the body does with other substances. Usually the best bet is to just abstain for a few weeks and then hit it again. If you use anything that feels good regularly it eventaully loses its appeal. Its also why you don't see hardly any excessive abuse of cannabis among people because eventually the effects just become too normal feeling and lose there appeal. Its also why all drugs should be legalized. Initially they are appealling because they are illegal or taboo which just makes them more appealling at first. Then you lose interest in them when they become legalized.