There is one thing I started doing last year- sometimes trying writing with my left hand, just for fun.
I'm a rightie, so the first letters I wrote with my left hand was a near-illegible mess. But as I practiced for a few weeks, my left-hand handwriting actually started to look a lot like what I used to write with my right hand.
Here's some trivia: It's not your hand that's making your handwriting look the way it looks, it's your brain. I've heard of a guy who was paralyzed and unable to use his hands, so he had to write with a pen in his mouth!! Believe it or not, his mouth-writings (as compared to handwritings) became similar to what he used to write with with his now-lost right hand!
So to improve on both imagination and logic, the solution might be as close as changing the hand you normally write with.