Number 1) on my list for improving walking skills is walking backwards, mostly because it forces us to think about how we move on our feet and hold our bodies. It can help with balance and co-ordination, relieve poor postural habits, and stressed knees, and strengthen shin, calf and ankle muscles and tendons (tibialis anterior, gastrocnemius, achilles tendon). 
Newby: Try a few steps hanging onto a wall. Rest. A few more steps. Rest. Repeat a few more times.
More confident: On a treadmill at slowest speed for 5 minutes. Increase speed with capability.
It's a breeze: Anywhere it feels safe—you won't run into things, trip, or be run into. Keep your senses alert!
Athlete: Run. Many field sports require quick changes of direction. Incorporating running backwards into your drills, if you don't already, will increase your directional stability.  

One foot in front of the other. Simple walking. Sounds simple. It did take about x million years of evolution to get us on our feet. Unlike our four footed friends who tumble then stumble into the world, we humans require an average of a year on the planet before we have all the neuromuscular control to amble independently. The muscles we work and develop to get vertical are the same ones that sustain us throughout our lives. Lifting our heads, arms and legs in prone position, touching hands to feet in supine, rolling over and pushing up, all work our core. 
 
Squats, lots of practice lifting up feet and finding our centre of gravity, support our leg strength and balance. We have this remarkable achievement by the time we are two, but by age five social practices dictate that we pack it away and resume our 6 month old position of sitting for the remainder of our lives. So much for ground gained. Walking type activities are consigned to recreation, if we have time for it. When we finally might have more time for it, our bodies have changed, and simple walking has become a challenge. Things hurt, get tired and become less steady, but what's lost can be regained to some degree. My next few posts will present a few exercises to help re-establish the posture, strength and neuromuscular conditioning to make that walk in the park a walk in the park.