To choose a niche which can have a glorious start and great sustainability, you need to do a few things. Follow these steps to get the niche you want. A no-brainer self-sustaining small market where people will flock with the least effort on your part.
1. Decide on your passion. What is your passion? If you know something which only a few people know about, and are very passionate about it, then that is a good start. You need to be passionate about something in order to make it work. You need that passion because you will encounter days when you are not motivated, and when you cannot write a single word without thinking hard. If you are passionate about something, you can write about it in your sleep, and still be understandable, readable and interesting. That passion is now your keyword. You will write a lot about that keyword, so you better be comfortable with it.
2. Find the right long-tail keyword. Using your passion, you now have a keyword. The next step is to refine it. When you use that keyword on a search engine, you will find a million web pages about it. That is how many competitors you have. You will never win against a million competitors. Go to Google Adwords and enter your keyword. Google Adwords is an easy to learn tool where you can find out the number of web pages which a specific keyword. Also on this site, you can refine your keyword search to find those keywords which have a lot of searches. You want a keyword which has few competitors but a ton of searches. You will end up with a long tail keyword of about 3 to 4 words which has around 100 or less web results, but more than a thousand searches. Create a short list of these keywords.
3. Go to Tumblr and look for images. Tumblr is a high volume website with plenty of micro-bloggers who re-post, and share pictures. Use your long tail keyword list and search for pictures and blogs about it. You need a keyword which has a lot of pages which post, share or repost pictures for your long-tail keyword. You will need these websites to share their posts. You can do this automatically using third-party automation tools on the web.
The strategy is simple: write about your passion to a large number of people, with only a few other persons talking about it. These people have little choice but to go to your site because you are passionate about it and you keep the site updated. If you cannot update the site with a new blog post, then post a picture from Tumblr, or Pinterest, or from Instagram. Remember to link to the original post and give attribution.