Decide first on your reasons for creating a blog: to develop your ideas; to develop your understanding; personal reflection, etc.
If your blog is for an assignment, check the guidlines. In particular: word limits; frequency; timing; style and tone.
Writing regularly on a theme provides opportunities for your mind to generate different perspectives. In the time between posting, your brain may still be working away at an issue, and you may then find ideas forming more fully the next time you sit down to write.
You may be required to write a reflective blog as part of a research project. This is to encourage you to give thought to one or more aspects of how you: conceptualise the task; plan your work; apply learning to new contexts; and evaluate what happened, drawing lessons from the experience so that you do things even better next time.