Balloons on mail box, signs on main roads that will leas them to the location easier. Advertise on craigslist for free... also serve cookies and coffee.
For feedback, make a survey asking people who come to the open house to fill out.
I usually ask for their email address, as a lot of people are hesitant to give a phone number. I never want to seem invasive.
I will ask on my survey what they think of the house, the price, and the condition. I also ask if there is anything they would like to see changed
'Just simple feedback so I can let the owners know.
For the most traffic... have a yard sale on the same day. You would not believe how many folks come out for a yard sale, and sometimes they are interested in the house. You just NEVER know.
You do not at all have to spend a lot of money to have good traffic to your open house. If your price is good, and it is well advertised, you will have a good amount of stop ins.