The price has to be right in the beginning. Everyone wants top dollar however, the right price (often a competitive price) will bring a choice of qualified applicants.
You shouldn't host an open house for a rental. You only want to show the property to prequalified inquiries.
Most PM software syndicates to dozens of rental sites however, IMO, Zillow still provides some of the best leads. Make sure you are listed there.
Feel free to post a link to your listing and I'm sure the group would be happy to make suggestions.
As someone else mentioned, each month it sits vacant costs you a lot. If the basic blocking and tackling is correct (good pics, good description, allows for pets, priced right, listed on the correct sites, PM is responsive to inquiries) then you need to pull the rip cord on price. You can do this either by lowering the monthly rate (suggested) or by offering a lease special (like 1st month free rent or a free flat-screen TV or a free year of cable, or whatever).
Good Luck