Not only do you need to know what your site’s purpose will be, plan out the content (blogs and pictures, etc) that you’ll share, but you also need to know how to set up your website.
Think twice before you start your blog on a free platform, especially if you’re thinking of buying your own domain name because attaching a domain name to a free site often costs more than a complete self-hosted site.
If you plan on using your blog to make money, or even just want people to take your page seriously, I cannot recommend using WordPress.org and BlueHost to set up a self-hosted site.
Free SSL certificate (this means your site visitors won’t get a horrible warning that your site is not secure, very worth it!)A Free domain name for the first year (um YES!)24/7 support, which will come in handy!