No matter what your job is, the Work at Home Mom, Dad or single person has to be super organized. If you are not already a bit OCD...get there. If you have a person close to you...that you can trust not to throw out all of your favorite things ask them for help. I'm so glad that my mom is here to help me get back on track.
Files and folders are a must. Don't forget to label and keep them in a convienient place for easy access. There's nothing more frustrating for me to leave a file upstairs when I'm downstairs in my home office. Up the stairs I go again.
How to keep the kids out of your area? Be sure that they have their own space. If you're working offline and not on the phone, let them be closer to your. For some reason, my children seem to sense when I'm on the phone. I've learned to let them hang out close to me when I'm offline---this is great for them to read outloud to me or play a video game that's in my view to cheer them on.
Hope it helps...please share your tips.