Making money online isn't just about picking something solid and working at it. That's the biggest part of it, yes. But all the work in the world - even on something that has a real shot at success - puts zero $ in your bank account.
Doesn't matter if you build niche blogs, sell a service, do affiliate marketing, or make and sell your own stuff. Until you decide "it's good enough" and pull the trigger, all it represents is the time & money you've invested in it. It's just potential income until you let go and put up that order form (or affiliate link, etc.).
I'm not for a second suggesting that you put out garbage. But I think there just might be a bigger problem at the other end of that spectrum. Seems like a lot of people I talk to and hear about are waiting for that next edit, or that extra bonus to add, or to get some better graphics made, etc. etc. Or, they worry to the point of exhaustion that what they've created isn't quite good enough.
You know what? Most of the time, it's better than good enough when you think it's not quite good enough. Seriously. Ask anyone who's been in this game for awhile and they'll tell you about all the worry they've put themselves through for nothing. You're so much harder on yourself than your customers (or site visitors, etc.) will be on you and your product or service.
Accept that and get beyond it. Pull the trigger! Start getting payback for all your blood, sweat, and tears. Waiting until it's "perfect" (whatever the hell that means) just means you getting a day older with nothing to show for it.