Don't hyphenate from one line to the next. Don't right justify your text. If you use a formatter, use a 50 column line width. I reply to all submissions, with either a yes or a no. If you are accepted, your joke will be queued and will go out in the next several weeks.
Topical jokes go out faster.
Some replies don't make it due to bad mailers, I'm afraid. Please don't post the joke to rec.humor until you have received a rejection, as it makes me look like I'm duplicating. If I reply to your joke, and you want to respond, you must include a description of the joke in your response. Remember that I send out around 20 rejection notices a day, and when I get your reply back, I won't have the faintest idea which of many jokes you're talking about. If you add extra, I just have to delete it.