Sherrine has some great suggestions.
I really like wearing wool socks and wool sweaters. Flannel-lined jeans or slacks are good, too. Also, wool mittens are great.
There are heat packets you can put in your boots or shoes, but I haven't tried them. I believe they are called Toasti-Toes or Foot Warm Up foot warmers. For hands, there are Hothands. Farm or hunting-related stores often carry them.
If a person has diabetes or circulatory issues (or any other concerns about using these), check with your doctor, first. I have heard they get pretty warm, so that's something to be aware of, too. Use caution, obviously.
I really don't know how well these work, but have heard hunters use them pretty often.
Wearing a scarf around your neck helps keep you warm, too. And it helps to wear a knee-length coat, rather than a waist-length one. I've found some good deals on coats at church rummage sales and second-hand shops.
Long underwear helps with the layering. There are now some pretty colors for women, rather than the usual plain ol' white.
Don't forget warm boots if you live in a snowy area--they are wonderful! I always make sure I buy some that have soles that are good on ice, for obvious reasons!
Good luck and best wishes.