Before you buy a bike
First, figure out what kind of riding you will primarily be doing.
Will you be riding on bike trails, or off road cycling or will you be riding for fun on pavement with your children?
Why are you buying a bike? Is it for fun, for getting in shape, or are you interested in serious competitive biking?
What kind of riding position feels best? Hunched over in a racing bike or upright on a cruiser.
How far will you be going? To the grocery store, ten miles, twenty miles or cross country? And how often?
The more you know about yourself and your future biking experiences the easier your bike shopping will be.