I don't think you'll be learning very much from using line tools and copy/pasting your old assets for character drawing.

If you're looking to make rounded bellies and the like, try the pen tool from photoshop, or the closest equivalent for your particular medium of choice.
It's entirely possible with the pen tool and a few other tools to create Disney and anime quality art with just your Keyboard and Mouse if you practice enough.

If you're using MSPaint and can't afford a higher end art medium, give GIMP (Which is absolutely free) a download and try it out. There are lots of tutorials out there for it that could really help you make your art look more organic. And less angular.

Take it slow, and good luck. Improvements won't come overnight.

I used PowerPoint at the time.
OK.