Your heel in either men s or women s shoes should not slip upwards while walking. The heel is beveled where it touches the ground first as you step forward. DO NOT buy shoes where the heel actually flares outward from the shoe or where the outer sole of the heel is significantly broader than the shape of the rounded heel upper. If you cannot bend the forefoot of the shoe with one or two fingers as you hold the shoe in your hand, do not buy it for walking. The shoe is made of quality material with quality construction.
Leather is excellent because it lasts well and it breathes.
Check the stitching for neatness and regularity. The outer sole should be fairly firm. Avoid very soft, cushy outer soles that you can easily dent inwards with a fingertip you need solid support more than the feeling of walking on a mattress. Soft outer soles do not support, stabilize or protect, and the material tends to break down quickly with use. Some running shoes work well for walking.