You know, it would really help you to take a class. I thought I could do it on my own - it looks so easy! - but I just made a mess of it.
You will need to drop your feed dogs and use a darning foot. When I teach this, I have the students start with making loops (like strings of cursive letter i's and l's) and then a spiral and then write their names and other words. It's actually harder to follow a pattern than do it free-motion. Practice on fabric that you absolutely don't want!