You won't be able to do it this year, not a chance, even if you could get a venue you wouldn't get into any of the programs.
My advice would be to book it early early early and research the different companies, some are very good, some are terrible. When you book a venue, ask for photos and look very carefully, we got told all sorts of guff about our venue and it was shite! Also block book a hostel early for your cast, all the hostels are booked up by early summer just for performers.
Make a metric fuckton of leaflets and make them eye-catching, get the cast to give them out, don't pay anyone, the paid leafletters are terrible. Get them dressed up and doing something odd when leafletting. When I was leafletting I pretended to passers by that they were magic charms against sharks but would only work if you kept them dry. Half an hour before your show start writing special offer on the fliers and give them to people saying they will let them in for free, more bums on seats is always a good thing even if they are not paying.
Think very carefully about how much you want to charge for tickets, more than a fiver will put many people off, free shows do not mean you are terrible. If you do free fringe you get the venue for free and have a bucket at the back at the end, this can make more money than tickets. I have seen some excellent shows at free fringe. Also don't expect to make a profit, nobody makes a profit at the Fringe.
Write to every magazine you can think of, Three Weeks is a good place to start, you want as many reviews as possible, chase them up as they will forget about you.
Have fun, its a great experience.