Every situation and person is different; the answer, therefore, suggests gathering some individualized information and then also includes some general safety strategies.
First, assess and address your mother's individual situation. A visit to her physician and a discussion about falling as an issue may result in specific strategies that would be more pertinent and helpful to her as an individual. You can go here for a list of questions to ask the doctor to get this conversation started: http://www.nlm.nih.gov/medlineplus/ency/patientinstructions/000254.htm
For example, your physician may prescribe physical therapy to help address her balance or occupational therapy for a home assessment so that you would have help and expert guidance in making sure her home is as safe as it can be for her. These therapists can help with making sure that your mother has the appropriate footwear as well, which can also be a factor in falling. Or, perhaps vision is an issue for your mother, so a trip to the eye doctor may be indicated. Or, perhaps actual construction work is needed to ensure the outdoor stair area is safe, so you might want to contact a certified aging-in-place specialist. As you can see, there are many factors that may be working together to make this issue of safety more complex than it seems at first. These or other interventions may be strategies that you want to pursue in any case, based upon your knowledge of your mother's situation and her wishes.
That said, there are some general things that you can look for in terms of safety.These tips come from information provided by The University of Kentucky, the University of Florida, North Carolina State University, and eXtension. I have provided the sources for your reference at the bottom of this message.
Make sure that your steps, the porch area, and the walkways are in good condition. The porch or stairwell should be protected by railings, or otherwise protected.The stairs should be clutterfree, and must be kept free of snow, ice, oils, or any substance that might cause a fall. That means that there might be a need to ask someone to spread sand or salt on icy surfaces or to clear snow. Stair treads that are the same depth and the same height, and that are closed, can help decrease the chance of a fall. Too, the door threshold itself may be an issue and may need to be lowered.
Make sure there are handrails and that they are sturdy and securely fastened on both sides of the stairs and that they extend beyond the end of the stairs. Hand rails in hallways can be of help, too.
The doorways, steps, porches, and walkways should have good lighting with easily accessible lightswitches.
When using the stairs, one hand should be free to be able to use the handrail.That means getting help to carry in heavy or oversize packages or other items that can make it hard to see or don't allow use of the handrail.
Perhaps you might be interested in remodeling the home to eliminate the steps...there would be much more information to help with that, but one place to start is:
The Center for Universal Design:
http://www.ncsu.edu/www/ncsu/design/sod5/cud/pubs_p/docs/residential_remodelinl.pdf
http://www.ncsu.edu/www/ncsu/design/sod5/cud/pubs_p/docs/Home%20Modifications%20and%20Products.pdf
University of Kentucky: http://www.ca.uky.edu/agc/pubs/fcs7/fcs7191/fcs7191.pdf
University of Florida: http://edis.ifas.ufl.edu/as042
eXtension: http://www.extension.org/pages/Concerns_for_Home_Safety
You may also be interested in this information from the National Institute of Health on Falls and Older Adults: http://nihseniorhealth.gov/falls/toc.html
