“Do I look presentable?”

You're going to a formal dinner for an association that you're a member of. You have to dress up in a suit, which you're not used to. After you get dressed, you ask your roommate if you look OK:

Do I look presentable?

(something) looks presentable

Looking "presentable" means looking good enough for people to see. In the example above, the speaker wants to know if he looks good enough for the event he's going to.

You can use this phrase to talk about people, as well as things like your home:

Let's start cleaning up a little. We want the house to look presentable when grandma comes over, don't we?

Or your work:

We should be able to make something that looks presentable by the end of next week.

Say that something looks "presentable" suggests that it usually doesn't look good.

"Presentable" can also be replaced by "OK" in most of these examples:

Do I look OK?

We should be able to make something that looks OK by the end of the week.