Make money your god and it will plague you like the devil. – Henry Fielding, eighteenth-century novelist and satirist.
Becoming a Mercenary does not pay: do not start a business for the money alone. Here is why: starting and running a business always takes more effort than you first expect.
Even if you identify a business that will largely run itself, setting up the Systems (discussed later) necessary to run the business requires persistence and dedication. If the only thing that interests you about an opportunity is the money, you will probably give up well before you find the pot of gold at the bottom of the landfill.
Pay very close attention to the things you find yourself coming back over and over again. Building or finishing anything is mostly a matter of starting over and over again; do not ignore what pulls you. The trick is to find an attractive market that interests you enough to keep you improving your offering every single day. Finding that market is mostly a matter of patience and active exploration.
That said, do not ignore “boring” businesses until you investigate them; if you can find some aspect of the work that interests you and keeps you engaged, mundane markets can be quite attractive. “Dirty” businesses like plumbing and garbage collection certainly are not sexy, but they can be quite lucrative because there is a significant ongoing need combined with relatively few people willing to step up and meet the demand.
If you find a way to make a necessary but dull market interesting enough to pursue, you might have discovered a hidden vein of gold waiting to be mined.
This concept by author: http://book.personalmba.com/mercenary-rule/