A science blog is you personal booklet to the world. It is an online journal where you can write articles and include almost any type of content: photos, videos, text, sound, illustrations, etc. There are almost no limits to the digital communication you can do via a blog. It is flexible, easy to use and most places also free to set up.
The many praising words about blogging are downplayed by the challenge of marketing and advertisement. Not ads on your blog, but advertising your blog to reach the audience you set out to reach. After all, if no one is around to read your posts, your science communication efforts are not paying off.
There are many platforms to use for blogging. WordPress is probably the most widely used platform providing many free templates and intuitive designs. Try to choose a template that is responsive, i.e. that changes with the hardware. This makes your blog look equally nice in a browser and on a smartphone.
A science blog should have an advertisement platform and for this Twitter is very useful. You can link to you posts, call out to journalists (via hashtags and handles) and generally make some noise about your work.