First you need the "Great" script. A really good script won't get you the money that you need to produce the film. It MUST be "Great" or it will not get a second look. Remember, you will not get a second chance. The people that read these scripts have too many on their plate to give you a re do.
Weather you write the "Great" script or pay someone else to write it doesn't matter. Once you have it, you will need to find out what the budget is for filming it and find out how long it will take from "Action", to "In a can". A great place to start this is www.filmbudget.com.
Once you have your budget and shooting schedule, you will need to find out what kind of revenue your film "could" generate. You will be unable to properly market your film without this. A great company to work with is www.filmprofit.com. They will give you comparable picture reports that show you all potential income streams and how long it will take to collect all of the money that is on the line. Every investor that you will approach is going to need to know a potential "ROI" (Return On Investment) and how long it will take to recoup their initial investment.
Now you have a complete package! Make a list of any and all potential investors that you know. Start by calling each one of them and asking them if they have any desire to invest in a Hollywood feature film. Set a face to face appointment with them and show them in detail what your objectives are. If you complete steps 1-3, you will most likely impress them. Just because they are impressed doesn't mean they will want to give up their hard earned cash! Break up the cost into units, and decide how many units you want to "sell". Its similar to purchasing stock in a company.
Once you set an appointment, be early and prepared with all of your hard work. Before you talk money, make sure that you have given them a query letter. This will consist of no more than one page that explains your story and why you wrote it. Once you have done that, simply ask: How many "units" can I put you down for? If you get a no thank you, keep your head up. Nobody said this would be easy. Keep going, keep scheduling appointments. This is marketing, and marketing is a numbers game. Eventually, you will get a yes.