There isn't much generic advice one can give, every species has different requirements for successful care and breeding. Short of do your research and make sure you meet the needs of whatever species you choose, I'm not exactly sure what else to say.
Breeding aquatic turtles can be difficult, because they need water, and a significant area of land to bury their eggs on. Breeding amphibians can be a difficult prospect, you have to make sure the water is well aerated, and the right temperature at all times, plus tadpoles can sometimes be frustrating to feed as they usually prefer native algaes, but again, that depends on which species is chosen... read up.
