I am sitting here retouching a big project for Ariat International, as I will be for the next couple of weeks, and I had something pop into my head that I wanted to share with you guys.
First of all, I use a Wacom tablet for all of my retouching, and if you're interested in retouching you should invest in one sooner rather then later. What the tablet does is allow you to use a pen instead of a mouse, which makes you quicker and more accurate. All that aside, here is my quick tip: LOOSEN YOUR GRIP!
A lot of people think that if you grip your pen tighter you will have a smoother and straighter line, the opposite is actually true. If you learn to have a looser grip on your pen you will have less hand problems and your lines will be smoother. This is actually something I learned when I was studying calligraphy, and now it has come full circle to my retouching.
So there you have it, loosen up and be awesome!