RE Marketing, create some flyers or do something quirky like lollypops with a paper tag advertising your event and business.
Go out and visit every local business in your area - say hello and tell them about your night and let them know you would love to add them to your event guest list and give them a flyer or promo item (whatever you are using)
Either get them to sign up there and then or to call/email to let you know they want to come and how many people etc. Take a lead name and contact details, also take note of the business they are from for your own reference.
This way you are doing some data collection at the same time as promo and hopefully will get an idea of how many people may be coming along. (not everyone that requets guest list WILL come but normally 50%+ will).