In my opinion, similar has a higher level of being the same compare to resemble.
For example:
1. My look resembles my father's.
I like look my father but not exactly the same.
2. The twin brothers have the similar look.
Here it means, the two twin brothers look very much alike that you can hardly differentiate them from each other.
For me similar = identical (maybe 99% the same?).
and resemble = look the same (to certain extend only.)
You should note that "resemble" (to resemble) is a verb and "similar" (to be similar) is an adjective. So the sentence structure will be different.
He resembles his father.
He is similar to his father.
They resemble each other.
They are similar to each other.
"Resemble" can be changed into a noun, "resemblance".
"Similar" can be changed into a noun, "similarity"
They share no resemblance.
They share no similarities.