Talk about the way that something looks with the phrase "what ___ looks like". This phrase functions as a noun:

I don't know what he looks like.

You can talk about how something sounds, smells, tastes, etc. in the same way:

What it smells like is not as important as what it tastes like.

This expression is a bit casual. A more formal way to express the same idea is "how ___ looks", "how ___ sounds", etc.