hi
right the st up:
depends on species, as a vague guideline, a fish tank(min of 60cm normally)
what i do is i get another piece of glass/pvc, that is as wide, but only 1/3 of the tanks height and seal it(careful, some glue is poisonous) at the bottom, so that one side can be used as a pool, while on the other side you can then go and add moss, and plants, some peat maybe, basically a place where newts can hide,and be above water.
instead of the above you could just place a large bowl of water in the tank, but the first suggestion makes for a lovely show tank.
FEEDING
depends on the species. mosly blackworms, earthworms, small crickes for the larger species, and if they are aquatic(axolotls, check them out, they are great, there is a section of the forum devoted to them), or they spend time in the water, then bloodworms, or shrimp(not wild) or frozen bloodworm
