Ideas For Investment Groups

I am trying to get an investment group together...no particular location...to get a guarunteed ROI within one year. The part I am unsure of is how to go about finding the investors and how to present the idea to them. I am working with a guy who owns a construction company, buys the land, and needs loans to build on them. He gets plenty of pre-sales, and therefore gets a profitable ROI for all parties. I appreciate any help. Thank you.