1. Drink lots of water (actually a very dilute lime juice/cranberry juice mix). I aim for 4 litres/1 gallon a day, more in hot weather.
2. Don't drink spirits (specifically - note to self - half a bottle of bourbon, no matter how delicious). They cause some weird kind of dehydration, which makes the stones painful.
3. If you start getting discomfort from a stone, drink more water. It seems to 'float' them somehow, and can usually make the discomfort go away.
4. The stones act like little breeding grounds for bacteria. So, if you have stones you will be prone to chronic infections. If you are a chap, then this can lead to chronic bacterial prostatitus, which can cause all manner of problems, leading to a having a catheter fitted. But, if you have bladder stones, the stones will break the little plastic widget that stops the catheter from falling out, which means it has to be refitted. So, you may need to take a low-level antibiotic like nitrofuratoin (there is some evidence that cranberry juice can also help, because it reduces the stickiness of bacteria).
5. If you are passing a stone, and they offer you morphine, decline it and hold out for something more powerful. Morphine seems to contract the tubes, only offers partial relief, and makes the problem worse in my experience. I once had an IM injection of (something beginning with pent~ - I wasn't in the mood to take notes at the time) which worked very well.
6. Avoid foods containing high oxalate levels, like spinach.
7. Don't take medical advice from strangers on the internet (like me).