Decide on a general size and type of boat based on the type of cruising you will be doing.  Establish priorities such as safety, speed, living space, ventilation, storage and ease of handling. Avoid traditional boats with long overhangs or overly heavy displacements. They won't go to weather and will bob and roll going downwind.  Some of the newer boats combine the traditional look with a modern underbody and are acceptable.  We've personally gone with the philosophy that speed reduces exposure and would lean towards the faster boat.  However, it still must be strongly constructed.  In sailing performance everything is a compromise. 

FINDING THE BOAT: 
Once you have decided on price range and boat type the fun part begins.  Don't limit your search to the local area.  The best used boat buys are often in places where boats gather.  Check Florida, Hawaii, California or even New Zealand for some of the best deals.  High slip prices often encourage lower boat prices as well as end of the cruise "let's sell the boat" mentality. If you decide to buy a new boat the decision will be between a production and custom designed boat.  Generally custom boats have a significantly lower resale value over production boats.  That said, a custom boat if properly designed should meet your exact requirements.  However, the route from thoughts on paper to the finished product can be exasperating. 

THINGS TO LOOK FOR: 
When you think you have found the right boat spend at least a day aboard exploring.  Use all your senses.  How does it look.  Housekeeping can reflect how the owner maintained the boat.  Go through the maintenance records looking for periodic maintenance and repeated repairs.  Does it smell bad, this could indicate the need for plumbing hose replacement.  Try the berths.  It is hard to stuff a 6'4" frame in a 6' berth.  If you are satisfied that this is the boat, set up the demo sail. The demo sail won't tell you too much you won't already know just from looking at the boat.  Generally, demo sailing weather conditions are usually favorable (who wants to sail in bad weather?). Therefore, spend the time looking at the sails to determine their condition.  Note any excessive vibrations while powering.  This could indicate engine alignment or other problems.  Try and utilize all the sails and sail on all points of sail.  Rig downwind or spinnaker poles, preventers and throw in a jibe or two.  These exercises will point out any equipment or rigging shortcomings. Once you find the boat that most nearly meets your requirements hire an independent surveyor.  I can think of no circumstance in which you would want to utilize a surveyor provided or recommended by the seller or broker.  In conclusion, know your requirements, look in the right place for the best buys and seek experienced, professional assistance.  Lastly, enjoy the shopping as nothing beats messing with boats.