Great start, I know how deceptively difficult animating a basic walking sequence can be. I would suggest a more pronounced bending of the knee on the forward swing of each leg, which will lift the foot from the floor, then straightening the leg at the start of each step. At present the shoe appears to slide forward and backward, in an almost cross-country skiing action. Also, the legs are not the only thing that moves when someone is walking. The hips swing and the spine curves, allowing the foot to describe a more or less flat path rather than an arc, and the whole body moves up between steps and down at the start of each step, etc. I know this all sounds complicated, but seriously, attention to these details will make a good animation excellent. You have a great starting point in the figure itself, it is very good, and it is worth spending the time on this.
