What the difference between "мочь" and "смочь"?

I know that мочь is imperfective and смочь is perfective, but I don't know the proper way of using them.

I think you would have to conjugate these verbs because I don't hear them being used often in the infinitive. When you conjugate them, the difference becomes more obvious.

Я могу. - I can.
Я смогу. - I will be able.

Он мог открыть дверь. - He could open the door. (not clear whether he opened the door or not)
Он смог открыть дверь. He was able to open the door. (It is clear that he managed to open the door)

смочь - emphasizes the completing of the action or the result, that "I will be able"

мочь - shows the continuation and repetition of the action that "I already can"

I bet there's more to it, but this is what I can come up with right now.

Hmm..Master Admin has taken the time to visit the little people of the board!

I thought it was a good explanation.