I like to add some doodling to my art work, sometimes a little, other times more. I like the extra element it brings to the piece. I have taken some online doodling classes and would recommend Joanne Sharpe (joannezsharpe.blogspot.com) if you want to learn to doodle letters and Stephanie Ackerman (homegrownhospitality.typepad.com) if you want to learn to doodle images.
I have found that I do my best doodling when I'm not thinking about it to much but just going with the flow. I have gotten some great inspiration from a book I bought that is all about continuous line quilting, the book talks about practicing the design on paper and that is what led me to use them as doodles on my art work. Here are some examples:
The book is by Cheryl Malkowski, Doodle Quilting - here is a sample of what is inside
Where do you find doodling inspiration?