I feel your pain. It can be hard to get out of the building if you're just "searching" for an idea. If you're passionate about the idea And/Or you have to make it work - those help. Depending on your concept and the target demographic, it's much easier to put yourself where they are - and just ask questions. (B2C products are great for coffee shops, B2B at lobby area of a conference [so you don't have to pay to get in]).
I like putting myself into the flow of traffic to force it. Cold calls can be difficult, but the fear goes away after a while.
If you're looking for something formal, the Lean Startup Machine is a great experience that helps encourage you. (Not affiliated at all).
