From previous experience, here are a few things that may help. Happy to fill out if needed.
Issue a Call for Papers (CfP)
You get a chance to speakers to pitch their ideas for talks to you. It allows people who may not be a big name, but have an interesting proposal to get a look in. You can then categorise them and run targeted tracks if you wanted. It also allows you to break out of the same old same old that tends to dominate conferences. Have a couple in reserve and ask that the successful speakers provide their slidedecks a month in advance so you know they have the material for the conference.
Allow an un-conference at the venue.
Talks often spark more debate and discussion, so if possible offer a room or two and a whiteboard with a schedule outside of it that anybody can schedule a short talk or discussion. It also allows those attendees who have a germ of an idea but not a fully developed talk to present it to any interested people in a more relaxed atmosphere. Google the idea if you need more detail.
Offer "Blind bird" tickets
You can get an some initial funds by offering tickets at a much reduced rate for the conference without announcing all the guests / schedule. Some people will buy because it is cheaper and take the risk of a 'lucky dip'. If they're regular listeners, they'll also most likely be re-assured that the quality of discussion is going to be better than previous paranormal conferences.
After this, you can release early bird tickets when you have 75% of the schedule filled and people have a clearer idea of who's going to be there and what the schedule will look like.
Sponsors
I think you probably know a lot in this area already, but don't forget to offer pitches for top and tailing any audio or video collateral you produce - sponsors often like this as they get much more longevity from their sponsorship. Obviously break it down into bands like Platinum(2 sponsors), Gold (3), Silver(3), Bronze(4). You can also offer Media partner sponsorships - they promote you ahead of time via their mediums and you promote them at the conference. Sponsors help to fill (and pay for) conference bags.
Lunches / Networking events
All can be sponsored to help reduce costs. How this is done varies - if you have a specific sponsor you might let them make the announcement of their sponsorship. If they have reps, they could work the room exclusively for that event. Do not do this for lunches/meals
just be discreet for those.
Venue
You've already covered a lot in the thread. But if it's in a hotel, obviously ask if you can get a room package as well. If it's not in one specific hotel, then you could be cheeky and ask around at a few hotels and see if you can get a deal. Make sure you have good Wifi at the venue. Plenty of power bricks; a flipchart or two. Check if they have an in-house technician(s) who come as part of the package - it's always tempting to think you can cover that, but on the day(s), you just want to be able hand off all that to someone else who does it day in, day out and be able to get on dealing with the other problems.
Internet conference
You could test a lot of things and remove the hassle of the venue by having an internet conference. You can use this as a pre-cursor to a larger conference at a venue. You can test specific topics with some people from the CfP activity and also introduce them to a wider audience. You could try a google hangout for the unconference side or for a panel discussion - and record it to youtube so you have a footprint to build on.
Will post more as I remember.