Make sure they do. Every word needs to work hard to justify its place on your panel. There is no place here for make-weights or space fillers. Make your words work, so your visitor doesn't have to. This means that you will have to work on the words.
Titles are vital.
By the time she's read this far your visitor will have decided whether or not she is going to read this panel. Put your main message into the title. This, of course, presupposes you know what that message is. There are other tricks you might try. I nearly added 'punning' to the list of p's because I like it, but not everyone does.