There are several types of arthritis that can affect your dog. Some of these are very treatable, others less so. In either event, I think it is a good idea to get her looked at by a vet.
In terms of general activities/considerations as a lot of the arthritis management truisms for us apply to them1:
Make sure that her weight is ideal. Heavier dogs are going to be harder on their joints than dogs at an ideal weight.
Certain forms of exercise can be really beneficial, notably swimming. Swimming does a couple of things here: relieves pressure on the joints and provides non-impacting exercise.
Keep her exercises less impacting in general. For example, softer surfaces for walks (grass rather than pavement) and reduce leaping around (especially jumps from heights).
In terms of medicating, I think it's best to talk the vet. There are some human medication options that can help, but best for your vet to recommend. If it is a treatable condition, then its almost certain there will be a regimen of medication to treat.
1 Blackwell's Five-Minute Veterinary Consult: Canine and Feline (5th Edition): Osteoarthritis, Appropriate Health Care