I use ground chuck for this recipe. If you want a leaner meat, you might need to add 1-2 tablespoons oil when cooking the beef and onions.
dice the potatoes in cubes no larger than 1 inch square or they won't be soft in the cooking time. Dice them uniform so they cook evenly.
add the spices after cooking the meat and before adding the liquid so they have contact with the bottom of the pan and get a little toasty and fragrant. This also helps distribute them evenly in the soup and not clump up.
If you don't have Ro-tel you can just add a can of diced green chiles to the soup.
I like to use the frozen variety of mixed veggies because it doesn't contain potato. The canned version has potatoes and they won't be the same as the fresh ones you are adding.
prep everything ahead of time and just mix in your slow cooker for an easy meal.
I love to top mine with a dash of hot sauce and some shredded cheese!