What worked best for us was to strip the ground bare. This gave us a really clean start to our project. We cranked up the weed eater and knocked all the grass and weeds down to the ground.
In doing this we disturbed some of our Upside Down paint lines so we had to refresh them with some more paint.
Now that we have a clean canvas so to speak lets get to work.
There is a high probability that you will be contouring your lot with high and low spots. Move the materials that you dig up from your river, pond or sunken garden to your hills or raised gardens. If you get lucky and find a large rock while digging don't bury it or haul it away, try to find a home for it. The more material you can reuse the the more money you will save.
One more thing to think about while you are moving things around is drainage. Make sure your property will drain properly. If you have to put in some drainage fields now is the time to do it.
Oh yeah one more thing. Be sure and stretch out good before you start working especially including your back. We don't want any injuries while we make our home beautiful!