Entrepreneurs always think that short pitches (like 10 minutes at an Angel group meeting) just don't give enough time for them to "sell" the deal. Au contraire! The goal of your first pitch is to intrigue and interest the audience in the business to get another meeting. This follow-up meeting, with a group that has already declared interest, will you give ample opportunity and time to elaborate on your deal.
Although it takes a lot of work to boil your entire business into ten minutes or so, a well done presentation really sets the stage. Remember, it is not so much about the product but the way of doing business with the product. There is plenty of advice on the web what such a presentation should include – reckon you need only about 10 content slides and a few miscellaneous ones with contact information and your introductory logo.
The same holds true for your first meeting with a VC. The chances are you will first meet with an associate who filter deals for the partner to see.