The response to designs presented this way is instantaneous. It leaves no doubt in a clients mind as to the end result. Presenting designs in context is particularly useful for large format work where physical proofs are out of the question e.g. billboards, shop fronts and vehicle wraps.
Better still, is to present the design on the actual building or shop front where the design is to appear (rather than mocked up on stock imagery). When taking the original design brief, ask for a site visit.
It doesn't matter how cool that poster design is or how creative that poster is if it's not presented well. I think I've almost seen it all; stacks of crinkled paper, projects mounted horribly crooked on matte boards and scrap books of color copies.
If you don't care about your own work, why should anyone else? Create an Indesign template you can use over and over with your own logo and slug line in a corner. Create a unique information bar, buy a domain name and create a website with password protection for presenting designs and concepts to clients. Think out of the box!And most of all, make sure to let your passion, knowledge, and enthusiasm out as you discuss your work. You are selling your work but you are also selling yourself!