I just put the potatoes, carrots and onions in the crock pot, put the roast on top and add a can of beef broth and gravy. You can put it in the oven for about 3 hours at 350f with much better results though.'
First, the best meat for pot roast is the CHUCK ROAST. I get the one that is flat with the bone, they are harder to find but some supermarkets will carry it. Also if the roast is too large, some supermarkets will cut it in 1/2 and sell you just 1/2. I know that Safeway and Fred Meyer will do that.
There are several ways of making good pot roast. Some use an envelope of LIPTON ONION SOUP and minced garlic and pour over the meat, with either either just water or also a can of Campbell Cream of Chicken or Cream of Mushroom Soup with equal can of water. You can add black pepper.
Personally I like mine simple. I slice thinly a 1/2 onion (depending on size), together with a lot of minced garlic, put that over the roast. Then I get Kikkoman Low Salt Soy Sauce and sprinkle some of that over the meat with maybe 1 to 2 tablespoons of water, with some black pepper. You can also sprinkle some garlic and onion powder on top if you want. That's it. Cook for 3-4 hours on high or until meat is tender. This is easy recipe and delicious over rice.
Go to YOUTUBE.COM and look at some of their video recipes. There's tons there.