The Entrepreneur's Golden Rule

Every successful business is conservatory in nature- which is to say that its value comes from undermining an inefficiency. There are two resources to conserve: money and time. Any activity that sufficiently lowers the expense of capital and time required to accomplish an activity will be profitable.

This leads to two questions:

1) How does my idea lower the financial cost of doing something?
2) How does my idea reduce the temporal cost needed to do something?

This leads to three functional targets for starting a business:

1) Things that take too long
2) Things that cost too much
3) Things that take too long and cost too much

And, finally, two considerations:

1) Who are the people who are most desiring or involved in the "thing" targeted in the above list
2) How do I increase access to my service to these people just identified.

Now, with your idea formed, go out and start that business! The money will follow if the idea is sufficiently satisfies the conservation rule.