Looks good, it's coming along.
Next, you might try implementing a crawl or creep gait. This means moving only 1 foot at a time.
Assume a stable tripod on 3 legs, step forward with the 4th leg, and then swing the body forward
using the other 3 legs, so you get a new stable tripod for support, and can lift and step the
rear-most leg.
If your servos are a little weak, the creep gait will work better than a trot [2 legs by 2 legs], as
there are always 3 legs down and supporting the frame.
This page may be helpful,