What helps me for letting go....I try to imagine that I'm a feather, slowly floating to the ground. Swaying this way and that in the wind, gently sinking. When it comes to the vibrations and other stuff, my best advice is to just ride it out. Be confident that you are safe, this is a natural thing that happens every time you sleep--you just happen to be conscious for it this time. Just maintain consciousness, be aware of what's going on but try to stay as an observer and be calm about it. The SP will usually subside and you'll enter the dream. If this doesn't happen...try visualizing your hands in front of your face or visualize part of your room. If and when you're able to see dream stuff, stabilize by touching dream objects as much as possible. Good luck.