Building for Yourself or Other People
You can find success building for yourself or for other people, but the key is to have unfettered access to at least one person in the demographic you're looking to sell to. Niches where you know someone on the inside (what I call a "warm niche") will be dramatically easier to succeed in than something you pick out of a hat based on keyword demand.
The problem with building for yourself is that unless you have hobbies other than software development then you are typically entering an already crowded market since every developer wants to build software for other developers. In general I don't recommend building software for developers for a number of reasons including the competition and the fact that most developers expect things for free.
With that said, if you have hobbies or interests where you find a need for an app/website then you are in a good position to build something for a non-developer audience since you yourself are probably an expert in what needs to be built.
In terms of keywords: there is no "right" value that you need to hit coming out of a keyword tool. Since traffic is only one-third of the equation (with the other two parts being conversion rate and sale price), your keyword numbers could come back at 300 searches per month and you could build a successful business if you have a high conversion rate and high sale price, or you might need 1500 searches per month if you have a lower conversion rate and sale price.
BTW - there is never a keyword score that's too high, but there is competition that is too high. To get an idea about competition do a search for a term you want to rank for and look at the top rankings - do they have a lot of backlinks and solid on-page SEO? Micro Niche Finder also provides a good SEO competition score in the column all the way on the right, the SOC column. The lower the better.
Regarding AdWords, it depends on your conversion rate and price. In general I hesitate when I see AdWords bids above $3.50 because that means you need a high price point to make it work. If you consider a 1% conversion rate your price point needs to be $350 to break even.
In conclusion, remember that keywords data is only one way to assess a market. Other ways include:
- Talking to real customers (which should be your next step after finding a niche using keyword info)
- Putting up a test site and sending traffic to it to see how many people will provide their email address based on your description or screen shots of a product you are thinking of building. You should do this after keyword research and before writing a single line of code.
I hope that helps. Good luck.