There are a lot of things to mention, but utmost of all important things is that you must fall in love when you set foot on her. If you do not get that feeling, then she is not yours.
Also remember a rule that I learned. Once you made a list of items to be fixed on your proposed boat, then you times the estimated money and time by three and you should be very close to your final values.
Lastly, sailing is almost 100% like flying, so you will pick it up very quickly if you are a fly by the seat of your pants pilot. The theory is the same, just the aerodynamic planes are vertical instead of horisontal.
Half the fun of owning a boat is finding the one you want - take your time and enjoy!!