First off, if there's a con you're interested in being invited to and you feel you have information that the attendees will enjoy, then by all means, ask them. There's nothing wrong with taking the initiative. You feel you have something to offer, right? Then let them know. What's the worse that can happen? They tell you they're not interested, that's all. They're not going to ridicule you all over the internet. These people are far too busy to do that. Seriously.
If you're interested in chatting up cons, create a con resume. A con resume is exactly what it sounds like... it's a listing of the cons you've attended and what you did at each. If you've done panels, list them out with a brief synopsis of each. If it's volunteer work you did, list that. Done art that the con used? Slide that in there, too. You can hand this to potential cons, true, but more importantly, it's a record to help you remember what you've done and when.
You could also ask panel attendees and past con staff if they'd be willing to offer testimonials about your work and about you as a person.
Oh, as an aside... don't try to impress upon people how important you feel you are by bringing up your "big buddies in high places." The goal here is to get you in as a guest, not your buddy. The con isn't interested in who you know. They want to know what you know. All you do when you play that card is give the impression that you're trying to puff up your own ego. This is a bad move.
A little pro-tip here, people who can do what they claim never need to puff their ego in that way. The very fact that they are not doing so is a clear sign that they are knowledgeable, confident, and reliable. True professionals know this trick, and can see through your puffing in an instant. They will also, just as quickly, write you off. So don't do it. Be honest about your capabilities and stick to talking about those capabilities.
"But being a GoH will get me respect and stop people from taking over my panels, right?" Not necessarily.
As someone who's been a GoH herself, I can tell you that being a guest won't stop someone from hijacking a panel. I've had it happen to me, and I've seen it happen to others. Here's an unpleasant, but true, fact... if a person has no respect for you and your abilities now, their attitude will not change simply because you're a GoH for the weekend. I'm sorry, people are just not wired that way.
If that ever does happen to you, remember that their behavior is a reflection of them, not you. You haven't done anything wrong. For some reason, they've got something wedged up their nose and they want everyone to know about it.
Yes, a few people may be dazzled by their behavior, but the greater majority will be annoyed. Those people came to see you talk, not the hijacker. And while they may clap at the end because they want to appear polite, they'll also come to your table afterward and gripe about the "rude person who ruined your panel."
So no, being a GoH isn't a guaranteed 'heckler free' pass. It will get you some nice perks, true. It's not unusual to have your table or your hotel room covered by the con. Sometimes the con will do extra things, like invite you to a nice luncheon or leave a gift basket in your room. A few will even cover your transportation out.
It's very important to remember that many cons want something in return, usually in the form of art or advertising. They may want you to drum up interest for the con on your site or blog. Or, they may want you to do some art for the con book. If you are asked to do something, do it and do so in a timely manner. Don't wait until a week past the deadline to do those drawings for them. You want to get invited to other cons, right? Then be a good GoH! If you build a reputation for being a good guest, you're more likely to be a guest again. It's as simple as that.
Until then, build up your con resume, work on your comic/credentials, and remember to treat panelist how you want to be treated. If having someone hijack your panel gets under your skin (which it should) then don't ever hijack the panel of someone else. You're not making friends and influencing people by behaving that way. You're being an arse. Furthermore, you'll be remembered as an arse, not just by some attendees, but also by the con staff. Just ask yourself, is that small moment of stolen glory really worth the reputation?
"If you believe in unlimited quality and act in all your business dealings with total integrity, the rest will take care of itself."
-- Frank Perdue
