I could have pretty decent handwriting for about an hour and then fatigue simply set it and most of my writing is an illegible mess. Not surprisingly, when I was young and we were graded on handwriting my grades were pretty poor.
Cursive didn't help much either as the continuous strokes simply meant I made more of a mess all over myself.
I was an okay sketch artist as a kid, so I had good pen control, just could never really adapt myself to the written word.
Lots of lefties go through all kinds of contortions to improve some of the situation, you'll notice Obama reaches around where he's writing so he can pull on the pen. I tried that for a while but the back and shoulder cramps were pretty spectacularly killer.
https://traceyricksfoster.files.wordpress.com/2009/03/obama-...
The main pens I've been using these days are disposable fountain pens [1]. They write great and somehow the ink rarely smudges, though more often than with the Jetstreams. But overall I find it more pleasant to write with fountain pens.
Even worse, for my own personal note books and random writing I use steno pads and write from the bottom to the top of a page. My wife hates it because when I ask her to read something I've been working on she has a lot of trouble reading it. But I've been doing it for so long it's natural for me. If I need to share something with people I can write "normally" or type it out. But personal use my system works for me.
Now I work for a big tech company and still carry a notebook + fountain pen + blotting paper to meetings, it amuses my coworkers.
If so, there must be a lot of products and techniques to accommodate their needs, which could help you.
[1] http://legacy.mos.org/sln/Leonardo/LeonardoRighttoLeft.html
At the moment I am mostly using Artline 200 Fine 0.4mm pens. These are not ballpoints and the think ink lines dry fast, so the text is hard to smudge. They are not without issue though. As the nibs are only crimped into place and writing with your left hand means you are pushing down and to the right; the nibs slowly get pushed up into the pen body. So I have to replace them when the nib disappears which is before the ink runs out.
If I am forced to use ballpoints for any lengthy text I end up rotating the paper close to 90 degrees and writing at an extreme angle to get the pen to drag rather than push across the page.
[1]: http://www.gouletpens.com/noodlers-bernanke-black-3oz-bottle...
But as a lefty, I feel like the proper experience of using them is pretty much off limits to me.