I had to look at my crock pot instructions to verify, but I have a low, high, and automatic setting. By using the automatic setting it first raises the temp above the danger zone before lowering the temp and slow cooking it. Otherwise it says to put it on high for the first hour then put on low for the next 6 to 8 hours depending on the recipe.
Good advice about cleaning and prepping as well as not taking the lid off while it is cooking. I had to get my wife out of that habit, explaining that every time she did that I had to increase the cooking time!