Bicycles riders (cyclists) on public streets have the same rights and responsibilities as automobile drivers and are subject to the same rules and regulations as any other vehicle on the road.
The keys to safe bicycling include being predictable, visible and communicating your intentions to motorists and other bicyclists.
There is much information on the web about riding better, safely and following the law.
A page on the League of American Bicyclists website summarizes how to ride better Riding Better. Some more specific topics are also covered:
Trailnet has a web page outlining bicycling and walking legislation in the St. Louis area.
There is an informative website on bicycle safety and rules of the road which is easy to read through in a few minutes.
Helmets must be worn on St. Louis Recreational Cyclists rides.