tell something by something *
tell something from something *

I can tell by the way you move into a town.

I want you to tell me by a month from now.

Tell your family by all means, but let everyone else believe what they read.

You can tell by the way they part their hair.

He could tell by their color, they had to be kept from him.

I can tell by the way you're thinking about what we should do.

I can tell by the way people look at him.

I can tell by the way she looks at them.

You can't tell anything just by the hours the kids are in school.

You could tell by her face how happy she was to see us.