Begin at the beginning.
You didn't really give us much to go on with that question. Examine your needs, your budget, and your capabilities.
Do you want a new one? Used? Can you spend over $200,000, or is your budget less? Will you be living in it full time, or just taking short trips on the weekends? Do you want a fixer-upper that you can customize to your preference, or a decked out model with all the bells and whistles? Are you travelling with 6 kids, or alone?
There is a LOT of expertise here at your disposal. Give them something to work with, and they'll help you along the way.