Stop moving your feet around midset. You should be driving your feet into the floor/forward, which will help with stability. Is your back set properly/are you squeezing your back tight before unracking? Your wrists are bent too far backwards; your wrists should be at about a 10-15 degree angle, with the bar over your forearm (this is covered in SSBBT3 and in an article or two on this site if you want more details/pictures).