Think about it. YOU have a great feeling about the job because you've done x, y and z. The problem is, THEY DON'T KNOW THAT! I'm not suggesting you put every case study you've written in the proposal, and I'm not talking about a few testimonials here either. I'm talking about building up a bank of case studies of businesses that have used your product or service to better their lives. Then, when you put that proposal together, you can include 1 or 2 perfectly relevant case studies. The video explains more. Side note: This is up at the Olympic Village in Barcelona. Clearly, where I'm standing is a rather opportune photo spot because, by the time I'm finished recording, there was about 60 people queuing up to take a picture in the exact spot I'm standing in. Also, look at the background... Now look at my t-shirt.