Fox's teen comedy Parker Lewis Can't Lose! hasn't been living up to its title. Facing CBS' 60 Minutes on Sunday nights, the show ranks 86th out of 97 in this fall's Nielsens. So executive producer Clyde Phillips plans changes to attract older viewers. For starters, Parker's frenetic visual style (extreme angles, fast cuts, special effects) will be toned down for a more relaxed look. High school student Parker (Corin Nemec) will acquire a girlfriend (Jennifer Guthrie) and a buddy in his mid-20s (Paul Johansson). ''It's a response to the audience,'' says Phillips. ''Last season could be considered somewhat cartoonish. We're getting more human.'' One thing Phillips doesn't have to fear is his NBC time-slot competitor, Eerie, Indiana. The amiably surreal drama was expected to take a bite out of Parker's audience but has so far proven toothless. ''We're baffled that the audience hasn't caught on to Eerie,'' says Phillips. ''And, of course, we're delighted.''