The term blog is a combination of the words web and log. However, a blog is more similar to a diary. It's a website where you post your thoughts on a regular, or semi-regular basis. The first thing you need to do to start a blog is to decide what your blog will be about. It's entirely possible to create a blog where you record your daily thoughts and activities. However, unless you're a celebrity, the only people that might be interested would be your family and close friends.
Another topic for your blog could be your hobby or a subject that you're passionate about. Because of your passion, creating regular blog posts won't even seem like work. But is there a large enough audience for the topic that you're passionate about to generate significant revenue? Your first order of business should be to determine how large is the audience for your prospective topic.
If your primary goal is to generate revenue from your blog? Then you need to choose a topic that will attract a large audience. And your blog posts need to stay focused on that topic. If you start drifting off on other topics because they peek your interest or because they're easier to write about, you'll lose your audience and your revenue.
Discovering which topics are the most popular is not difficult. One of the most popular topics is celebrity gossip. Another very popular topic is how to get money. Yet another popular topic is tech news and reviews. Each one of this topics presents trade-offs in the difficulty of creating posts. The difficulty with a celebrity gossip blog is in acquiring relevant photographs. Photographs that are legal to publish without violating someones copyright.
The how to get money topic is difficult because many people want to learn how to get rich quick with no work. They're not interested in learning about how to do any kind work to get money. Anybody can get money if they're willing to work. They want to learn how to get rich quick with no work, and unfortunately all get rich quick schemes are scams.
The tech news and reviews topic is difficult because it requires a bit of technical aptitude, and it requires money to purchase the latest high-tech toys to evaluate. Many tech blog writers get most of the products they review for free. This creates a conflict of interest, because if you give a less than perfect review, you can forget about getting any more free products from that vendor. Also getting products to review for free requires being an already well-known technical reviewer and time consuming and cooperative vendor contacts.
One way to choose a profitable blog topic is to perform a search with the phrase "top profitable blogs". This will return several lists of profitable blogs. The revenues some of these blogs are generating will be eye-popping. But remember, many of these blogs are generated by teams of writers. If you're going to be a one-person blog, choose a topic that one person can handle.
Another way to choose a profitable blog topic is to study Google Trends. Click on the More to Explore link, then in the left column, select Top Charts. On the top toolbar you can set a date range. You don't want to choose a blog topic that is too trendy because a few days from now its popularity may crash. You may want to study what was most popular over the entire last year. Learn how to use Google Trends. There you can get some very important information about what people are interested in.
Take your time choosing a topic for your blog. Make sure it's something you'll be able to write about. Also consider what related products and services you'll be able to sell when you're ready to monetize your blog.