The next thing you need is structure for your blog posts that supports your progress toward your goal. The structural elements you need are time, content and format. You must set a time at which you will create your blog post; typically this is a type of day, such as 6:30 am, but it can also be tied to some event, such as when you are on the bus home after work. The important thing is to set a time and practice creating a blog post every day so it becomes a habit. A source of content is necessary because if you sit around looking for content, you'll blow through your 10 minutes without even start writing. Find a content source, such as your recipe pile or the adventures of your pets, that either generates a new thing to write about every day, or that has enough back material that you'll be able to reach your overall goal. Finally, you need a blog post format structure that frees you from having to waste time figuring out the particular design of each post. For example, you might have a blog format that consists of one uploaded picture, a caption for that picture, a first sentence that describes the picture, a short paragraph telling when and where you took the picture and why, and a final paragraph talking about what the picture means to you. With a structure like that, you have split your work into tiny, manageable chunks that are easily tossed off - and quickly!
Finally, and most importantly, you must practice. Practice, practice, practice. There is absolutely no substitute for building experience by doing a task ten thousand times. Set yourself the goal of creating at least one 10-minute blog post a day, every day, for one year. The first few may be hard; hitting "publish" after 10 minutes may be embarrassing. However, after you have done this 100 times or 300 times, your work will improve and eventually it will be very good. Why not try?