Your quilting looks great.
I don't think it is possible to get too much practice. You can practice by sewing on paper, or with a dry erase board (be careful with that) too. Doodling first on something unimportant can help you to relax. Lori Kennedy is VERY generous with her free fmq designs and tutorials, and they are a fun way to practice. She is at The Inbox Jaunt here:
http://theinboxjaunt.com/
While it's good to try to be consistent with your stitches, it isn't necessary to be overly critical. Unless you are working on something that will go into a show to be judged.
Have fun.