whene I choose profitable niche from google keyword tool What I should select: 1.Competition=? 2.Global Monthly Searches=? 3.Local Monthly Searches=? 4.Approximate CPC=? please help me to determine profitable and "long term" profitable niche.
the more important is to select a niche which you can provide a good supply of content about it daily so you should make sure that its something you like and have a good background about it.
If you are choosing a niche based on it's profitability, you are already destined to failure and/or being banned. Do what Moustafa says ^ - create a quality site, generate unique, original, quality content based on a subject/niche that you are familiar with/passionate about..
The best niche is something you know about well and can write about. If someone tells you best niche is some rare disease. What can you write about it? Most probably you would copy paste stuff from other sites (written by medical professionals) and Google is smart enough to see the duplicate content. So waste of time. The other day, someone was telling he created a site about canceled postage stamps because he has postage collection as a hobby since he was a kid. And it is working well. This is not good niche but that guy knows about it in detail. Google loves it.