While this really depends on the type of fish you’re after and the conditions on the water, most anglers use a ⅜ inch mesh with a weight of 1 pound per foot as a universal net.
However, if you want to catch smaller fish in shallow water, go with a lighter and denser mesh (0.75lbs, ¼in mesh). On the other hand, if you want larger bait that’s in deep water, go with something heavier (1.5lbs, ⅝in mesh).