When a presentation or performance is "tight", it means that it's been practiced a lot and seems really professional. There aren't mistakes, or times when the speaker doesn't know what to say.

The word "tight" in this situation has a positive connotation. Another word with a similar meaning to "tight" but with a more negative feeling is "slick":

Her pitch was certainly slick, but it didn't really make me want to run out and buy one.