Glucosamine helps some and not others. It seems to be more effective in early OA, so you may find it helps, so if you can afford it and don't have side effects then go for it. The best thing overall is to keep your muscles strong. A trip to a PT might be of use to get some exercise tips so you exercise all the appropriate muscle groups. You need to address strength, endurance, flexibility, and proprioception (position sense) to fully make the most of an exercise regime, so make sure you do basic hamstring and quad stretches regularly, and practice balancing on one leg at a time regularly to keep your proprioception working well. Long walks, swims or bike rides will address endurance, and things like straight leg raises with weights will address strength. If you can maintain good muscles then you will find that even if arthritis takes a hold, you will have less pain and disability from it and it's progress should be slower with good muscles to support the joint. Don't do too much high impact stuff as once you have had damage (like a fracture) you are more likely to do damage from high impact work - it's healthy for undamaged joints but not healthy once some form of damage has happened.
Good luck, I hope this helps.
Kathy