What makes for a "best" niche for your blog? Well, my feeling is that the most important factor is picking one on a topic that you're comfortable with. There's alot to consider when choosing a niche. You need to choose an area that you know about, one that you feel you can say something useful, interesting about and a topic that invigorates you. You'll need to keep your energy, so pick something you lik.
From there, take a look at available tools like, Google Trends where you can examine the popularity of different search terms over time to see if they’re trending up or down. You want to find a popular or growing niche that’s trending upward so that you can position yourself as an expert for the future growth of that topic. Also try SeoBook and Wordtracker for keyword searches to find keywords to help in your niche decision.
You need to also check into the number (and quality) of other blogs and websites on your topic of interest (your potential competition) and whether the topic has potential for making you money. As we know, there will always be competition, look at the quality of the other blogs. Are they updated frequently, does the author do a good job on the topic, do you know more on the topic? Depending on whether it's your first, or an additional blog matters too. For a first blog, keep the topic a little more general, this way you can "fine tune" it as you progress. If it's an additional blog, it may be easiest to do a new one as an extension of an existing blog.
Need more help, ask. Pick a cool niche, then Blog To Great !
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