I think the main thing you may be doing wrong is going forward after you float the bucket. Doing that will almost always lift the front of the tractor because the bucket will hang on something. The loader arms connect behind the front wheels, and the rear wheels will continue to push even after the fronts are up.
You pretty much want to float the bucket going forward only on a hard surface that you are trying to clean up (like sand on a road, but it will wear the bucket lip fast).
For forward moving pickup of a thin layer of dirt, I usually float the bucket down (to set the level) and then take it off float. By going forward slowly while adjusting the amount of bite with the curl, I can take a thin cut.
Try floating the bucket and going in reverse. You will quickly get the hang of it for smoothing out a pile that you dumped. Curl the bucket for more bite when dragging, and leave the bucket level for finish smoothing. Once you figure it out, you'll wonder how you ever got along without a loader. Good luck!
- Just Gary