I think Jesus said "By myself I can do nothing" because his strength and power came to him through faith in his Father. Although Jesus was Divine, he took on on a human form and as a human knew he needed faith and reliance on the Father. The same as we all do. I think Jesus would see and hear his father by doing His Fathers will. I though I may not recognize it, God is always working in my day. Through prayer and mediation in Gods word I can learn to discern his will.