I figured it out!!! My feet sinking was driving me nuts... Go to "Edit My Shape" and under the body section (where you set Height) adjust "Hover" -- it affects how your avatar hovers (or sinks with certain shoes) over the ground and your toes won't sink. :-) Hint, you make need to type in a number to go up or down by one or two rather than use the scroll bar to be more precise.