We use than when comparing nouns using comparative adjectives.
- He is much more successful than I am.
- Mike isn't faster than Brian.
- These rings are more expensive than the ones we saw yesterday.
Instead of using I am you can simply use me.
- He is taller than me.
We use as...as when comparing nouns using an adjective.
- He is as old as my brother.
- She wasn't as happy as the other kids.
- I'm not as impatient as my girlfriend.