The market has changed with the brisk home sales. Currently there is a shortage of listings which is new territory for most agents. I have never seen this in my 25 years in the business. Most buyers are afraid to list their home because they have no where to go. This is a concern.
What I have been doing and it is working is purchase your new home from a builder (and of course use a realtor to coordinate everything) and begin construction of a new home. When you are about 2 months from closing on the new home, put your current home on the market. If your home is in great condition and priced correctly, it will sell in about 2 weeks. Builders will do contingency sales unlike home sellers. Besides new homes are priced in with resales and everything will be new and fresh and energy efficient.