Hi, Feebs! (cool screen name) I'm more of a non-drowner than a swimmer; my moniker comes from the fact that I teach aqua aerobics, which is quite different from traditional swimming. That being said, I'll presume you're skilled at several swimming strokes, so I'll make a few suggestions:
Create a 6-week swimming "rotation" that alternates every 6 weeks between steady-state lap swimming and interval-esque lap swimming incorporating sprint-laps followed by recovery laps;
Create a swimming session that alternates traditional, total-body strokes (front crawl, backstroke, breaststroke and 'fly) with kickboard drills that recruit only the legs (flutter kick is the most challenging; dolphin kick from the 'fly and whip- or frog-kick from breaststroking are good to do while anchored at the wall, as is flutter kicking);
Create a swimming session that alternates traditional horizontal strokes and vertical water-treading in the deep end of the pool;
Consider checking out whether your facility has aqua-joggers available for check-out and use in the pool; aqua-joggers are like floaty cummerbunds that you put on and keep your head above the waterline while you do running and long-lever drills. That is one handy piece of equipment, and can really expand your use of the pool as a training environment.
HTH -
A-Jock