Of course you can...but why? Typically this would be part of what a full time professional realtor would do for you, knowing what you are looking for and where, if nothing was available or upcoming. Inventory is tight right now and houses in desirable locations are going quickly. You want to make sure you are prepared to jump on something as soon as it hits the market- having you financing lined up and pre-approved and a professional watching the market for you. If you think its a great home, chances are so will someone else, and the really ready Buyer has the edge.
As far as you personally writing neighbors, I agree with Bob, it will probably weaken your negotiating position. My advice would be to interview some full time professional agents, find someone you are comfortable with, that listens to YOUR needs and have the work with you through the process. There are so many things that can come up, let someone with experience guide you through what is probably life's largest purchase. Best of luck. I feel an informed client makes the best decisions regarding their real estate needs. Let me know if I can be of assistance.
Broker Associate, GRI, SFR, NHS
Real Estate Consulting, Marketing & Sales
Prudential Tropical Realty
2539 Countryside Blvd #3 Clearwater, FL 33761