Many of these professional organization websites will give you an idea of what that job, or career, is like. A number of the websites have information about continuing education and other professional advancement possibilities - very few modern jobs are static, most jobs are changing and evolving over time; something to consider when evaluating a career is how much change from day to day and year to year suits you.
Some parts of some of these sites are for members-only (some memberships are free), they are included here because there is some useful information in the public sections of the website. There are many more professional organizations than the ones listed here. Beyond the ones listed here, a good way to find a particular professional organization is to do a web-search for an occupation and the words 'professional organization', or 'society of', or 'association'.