Heels do not need to be long and thin to be considered fashionable. But no matter what the length of your heel, take extra caution to keep your balance and place the least amount of strain on your muscles.
Step with your heel down first, then let the sole follow quickly and smoothly.
Walk with your toes pointing straight ahead or as close to straight ahead as possible.
Swing your arms as you walk for balance.
Keep your legs straight, close and parallel.
Take smooth, even steps; consider shortening your stride a bit.
Avoid walking on ice, slush, mud, grass, sand, gravel and grated surfaces, on which you can slip or sink. When in doubt, take off your heels and carry them across such questionable surfaces in your bare feet.
When climbing stairs, make sure both sole and heel land together firmly and simultaneously on each step. When descending stairs, only the sole of the shoe needs to be planted on each step.
Learning to walk in high heels is mostly a matter of practice.