I park the following way:
1) Get the motorhome as level as possible - sometimes shifting right/left or forward/backwards on the site will help you approach level.
2) Use the jacks to stabalize - two jacks should be just making contact. The other two can elevate the low end or side so you're level.
3) Never ever allow the rear tires to loose solid contact with the ground. This is where your emergency brake is.
4) Place 2"x12"x24" blocks under your wheels if you need to lift any wheels off the ground (back wheels can each be on a block if needed).
5) Place a 2"x12"x24" block underneath the jack if it is going to be on a soft surface.
This process has worked for me for years.