1. Make it very plain when announcing the tournament that it will be for fun/hobby. Make it clear that scenarios may not be from the rule book and may be unbalanced towards certain armies (like giving all units fleet, or having an entire game with night fight in effect). Let people know that this event is about having a good time and playing some goofy/different scenarios, not about being completely balanced so the only real variables are generals and their armies.
2. Very basic comp, ask people to bring multiple lists to a tournament, have a judge give it a quick scan. If it's a heavy list (and the crew we have in Austin can tell with a glance whether a list is heavy or not) either ask them to use a different list or dock their tournament points, nothing ridiculous, but enough to give people playing less competitive lists an advantage. Let people know that this will be happening and that there is no discussion on it. Maybe ban certain lists, like leafblower. I'm not a huge fan of that idea but I know even docking people who play leafblower lists might not make a huge difference at the end of the day and the super heavy lists would still not be fun to play against if you are a new guy at the tournaments (or hell, if you're me!)
3. Do wonky stuff with the force org chart, don't allow special characters, only allow a few specific special characters from each codex, encourage people to bring rarely used units (We're playing on a tech world, marine players who bring a conversion beamer and who can keep it alive until the end of their mission get a bonus point, or something like that). Try to break up the old hyper-competitive way to build lists. I know I use Lysander as a crutch, keeping me from using him would make me think in different directions and would remove a really tough nut from my list that would make it easier for a newer or less competitive player to have more fun.
4. Don't make the prize support entirely about getting the most victory points, the overall victor should get something. But people who come in with especially creative/fluffy lists, excellent paint jobs, conversions, etc should get something as well. Maybe have some kind of door prize for people who have never been to a tournament before to encourage them to come back. The stuff I listed are things we do already, but the point i'm trying to make is figure out a way to give out awards that don't reward people for coming in with a tuned up list and stomping baby seals on a hobby day.
5. Make the tournaments an entirely different format. Steve was talking last weekend about doing a heresy era tourny/1 day campaign. Get two teams of heresy and non-heresy imperial players together, winning team gets gift cards to dragons lair and a plaque, or something ridiculous. These Hobby tournaments need to be about having fun and doing something different, I'd love to be able to bring a fluffy themed list to a story driven event one day, sounds like loads of fun
A lot of the stuff I've mentioned has been tossed around before, and I'm certainly not saying that I'm a font of new ideas. But I would like to see our community be able to turn off the kill switch for a weekend and be able to come in and have a good time without the frayed nerves I've seen in the past.