I for one squeeze it between my fingers. If it falls apart / it's brittle, it may be too dry. If I squeeze it and it springs back, that's the moisture level I most often like. If I squeeze it and it sticks together, or it takes a bit longer to spring back, I will let it dry. Also ... too wet of a baccy will leave moisture on the fingers after you squeeze it. I guess it's trial and error, you will get used to it after a while.