Unless you want to be a "hack"...
Strong writers and bloggers need cross-training just like good athletes do. In otherwords, non-fiction writers need to know creative writing techniques to keep fit and creative writers have to be versatile. Staying in a comfort zone is an easy way for people to stagnate. Nowadays, change is the name of the game.
There are a few things that can help you get out of a writing rut:
1. Take the pressure off and just write. I write for B2B and if fear creeps in that I won't write something spectacular, it is harder to write anything at all. Have a writing practice aside from your "usual" (be it blog, freelancing or otherwise) and if the writing is full of spelling errors, not the best content, not meant for an audience, then it's OK. The goal is to change habits and innovate. And, an interesting idea might come out of flow-of-consciousness writing.
2. Change your writing style. You may have a really distinctive voice that has been developed over the years. How about changing it? Have fun with simpler words if you like jargon, or write with new vocabulary if you write simply. Try writing a paragraph using only alliteration, only metaphor, etc.
2. Paint a verbal picture with pen and paper. Go outside or someplace new, pick a focal point and get out the old pen & paper. Write what you see in very minute detail. Scribbling furiously on paper will change some of your habits and force you to think differently. Go back to your computer and rewrite what you wrote. You may skip words, details, and you'll notice that you get a different perspective than when you wrote with pen and paper.
3. The short and long of it: Pick something to write about. Write a bunch of long sentences stringed together. Write short sentences. Write a long sentence and a short sentence. Look at how that changes the tone.
A short sentence: Stop right there!
A long sentence: She stopped when the policeman cut her off in her tracks.
4. Another exercise in succintness for effect: Try writing haikus.
Each line should represent a visual concept. And if you write a line that is too long, that's OK too. The editing process will help to get you to where you want to go.
Roses in sunlight
Dew iced over from morning
It's a new day.
Also, it's better to expect OK writing on first attempts rather than a masterpiece. You don't want to set yourself up for disappointment, and it's the editing (or even deletion in exchange for innovation) process that takes you one step closer to perfection.