You'll find no shortage of books and classes on creative writing that encourage you to do various writing exercises--usually in private in your writing notebook.
"Choose a setting and describe it." "Flesh out a character." "Describe a feature of someone you know in vivid detail." And so on.
If this is what you really want to do with your time, and you believe these exercises will improve your writing, go ahead. Have a field day.
I consider them waste of time. To me, it's pointless to spend hours filling some private notebook with fragmentary writing exercises when you can get far more value by putting actual completed work in front of an audience.
Here's the problem with writing in your notebook: the only person who can give you feedback is you. And knowing how harshly most of us judge ourselves, that feedback is probably going to be negative. Soul-crushingly negative.
Forget all that. Instead of randomly choosing dumb writing exercises, why not complete a full work of writing from beginning to end and publish it on your blog? Do that a few times and you'll get real experience that lays bare your strengths and weaknesses as a writer.
Or are you too afraid to see your weaknesses laid bare?
Fine. Go back to writing in your notebook then.