Self-deprecate - to put yourself down, i.e. "My comics suck, I am not funny, but read them any way."
In addition, I have to say that a common mistake is the over-use of narration boxes. Your comics should be able to stand alone without you having to explain them. If you can't make sense of the strip without naration, it isn't a good strip to start with.
Of course, there are exceptions, but that is a general truism