One thing not mentioned here is diet and supplements. I've recently been getting light hip discomfort, so been looking into this side of things. Coenzyme q10 is meant to be good for joints, and chondroitin and glucosamine have possible benefits for lubricating joints and rebuilding cartilage.
Make sure though that you do your own research before trying these things though - they're pretty pricey!
It's amazing how the body will repair itself when given the right tools.
Also I try to stick to footpaths rather than tarmac - and have a good pair of trainers. The shock of running on tarmac with bad shoes should never be under estimated, particularly for the hips. Anything that can soften the blow (eg othopedics etc) is a good thing.