One way to choose a career is to make the thing you love the thing you do for a living. Get paid for your passion. BUT... there are other ways. The free market is the most effective democracy machine I have come across. When there isn't enough of something to go around, a freely moving price will make sure that thing goes to the person who wants it the most. Not needs it the most. Wants it the most. Want is defined purely by how much other stuff they are willing to give up to have that thing. Effort, intrinsic value, skill, empathy, intelligence, perseverance blah blah blah mean nothing. Supply and demand are king.
I say the free market is democratic because democracy is blind to deep analysis. Democracy doesn't care if you have done your homework. Democracy doesn't care about what we should do, it reflects what we want to do. Our politicians have to moderate what they say based on what we believe. We may say we want politicians with conviction who will lead us, but if they don't get the votes, they don't get the job. The same thing happens with the market. Even huge multi-national companies can nudge our wants and needs, but in truth they spend most of their time trying to respond to our wants. McDonalds is going through an existential crisis of sorts at the moment as demand starts to shift away from burgers to healthier foods. Politicians and Corporations do have power to influence us but we give them their jobs. What they provide is largely a mirror for what type of society we are. We get the leaders we deserve. We get the products we want.
We get the leaders we choose, and the products we want
If your job is your passion, you will likely have to do the same democratic flip flopping. Some people manage the tight rope brilliantly and get incredibly lucky. That is wonderful. Another way to go about it is to stop thinking about how to monetise your passion. Instead, create a mental wall around a certain amount of time you are prepared to do what you must. Without sacrificing any personal beliefs, do the thing that pays the most in the time you are prepared to give. FastCompany.com gives a few stories of famous creative minds that didn't give up their day jobs. "I was careful," Philip Glass explains, "to take a job that couldn't have any possible meaning for me."
What Glass is doing is putting the job in its place. It is a muse. It is there to allow his passions to develop elsewhere. His 'meaning' could come from his passion. Effectively this releases his passion from responsibility as breadwinner and allows the passion to be a homemaker.
If you can release your passion from supply and demand, it will have a democracy of one. You.