I had 6 snails at one point. Unfortunately after a couple of years they started dying one by one, and now I only have the one left who is hibernating. It makes me sad because I loved their little faces.
Some general pointers:
1) Keep them around 20 degrees or higher (don't forget they are native to Africa, so ensure they're kept warm)
2) If you're using a heat mat and have a plastic tank, don't leave it too close to the bottom of the tank, as it could melt the bottom (happened to me)
3) Clean the tank at least once a month - this requires transferring the snails to another bowl/tank while you do it...avoid using cleaning fluids as they can damage snails health. Simply use warm water and clean paper towels
4) When they breed, they do lay a lot of eggs. You either have to crush them all or freeze them.
5) Give them a sub-strait, but not too deep. You want to allow them to bury, but not too deep to encourage laying eggs.
6) Provide them with a calcium source (cuttlefish is perfect)
7) Change their food regularly, once a day or two (foods like cucumber start putrefying after a while)
8) Keep the tank humid, they like warm humid atmospheres.
9) Spray the snails and tank with water once a day. (Cheap spray bottle from a garden centre will do)
10) Buy a hydrometer and thermometer that you can store in the tank (the little circular ones are good)
That's all I can think of at the moment. If I can think of anything else, I'll post it later.