Its so hard to make the right textures for this game. I think all the TF2 textures come from 1 artist (not the model textures). That guy made them all since he knows the best what would fit. You can try to imitate them, but it's hard.
HMm see, you need to put the opacity of the cracks really low, also paint with a big fat brush really quick. Rules are: impressionistic, but the material always stay clear.
The first image than looks like it reflects water
The black image should get banned