I always use Google Trends to look at the niche popularity. It is based on Google Search, that shows how often a particular search-term is entered relative to the total search-volume across various regions of the world, and in various languages.

If you choose a niche that greatly decreasing in popularity, its likely that the amount of money you can make off of that niche will decrease as well. But if you find a “hot” new popular niche, the results could be incredible.

Hence, there are three criteria when it comes to identifying a niche through Google Trends:-

a) Significant search volume.
b) Upward trending search volume in the past year.
c) Very likely very low competition.

Hope it helps.
Alex

In one of the lessons in certification course, you identify your niche, then have ten, twenty, to thirty articles about it. If you can do that then you have a good niche.

Writing is the factor that makes it a good one. Even the best niche can be identified but if you cannot write about it, it is not good.

Hey. Here are a few ideas:

1. Keywords - if it has many keywords with a good search volume, that's a great sign. (Use keyword tools, Google Auto-Complete, and Google's related searches found at the bottom of every SERP.)

2. Products in Demand - if it has great products people want, that's a great sign. (Browse around stores like Amazon and find your niche's category. Checking out their reviews and ratings is a good way to determine if their products are great.)

3. Questions - if you find a lot of people asking questions related to your niche, that's another great sign. (Find questions on Quora, Reddit, forums, etc.)