My normal prep is about the same as for mustard greens, kale, or spinach (though spinach cooks faster):
1) Dice and fry bacon in large pot, remove bacon, leave bacon grease in pot.
2) Saute diced onions until golden brown, drain grease off
3) Add 1/2 cube chicken bullion dissolved in 1/2 cup water (or chicken broth if I happened to have some left over), diced garlic, and diced collard green stems. Cover pot, simmer 5 minutes
4) Add collard green leaves, cover pot, steam 10 minutes. Check and add water if a leaky lid causes too much water loss. I don't want a lot of broth left over but don't want it boiling dry and burning on the bottom.
5) Serve with bacon sprinkled on top, and a little vinegar, mustard, or hot sauce to taste