What are the differences between weak and strong verbs in German?

I know someone's already asked this before, but the answers given weren't exactly what was looking for. I'd like to know the difference between weak and strong verbs in German. For example, how do you recognize a weak/strong verb? If you could give me just one example of a weak verb and conjugate it with all the subjects in the present tense, and do the same with a strong verb, maybe I'll be able to notice a difference. But, at the moment, I don't understand that concept. So, any help would be greatly appreciated! Thank you! Tsch�s!