There are actually two different methods to make country style ribs juicy and tender. The first, low and slow, has been talked about in the above posts. You can use dry rubs, or sweet & sour sauce, with this cooking technique. You can also season with salt and pepper, and then spread a fruity sauce such as apple sauce, or peach preserves onto the meat when serving. Cooked bananas, spiced with cinnamon work well with the pork as well. You can use cherries, or pineapple, apple, peaches, apricots, or nectarines. Papaya works well too.
My personal favorite way to cook country style ribs is on my Webber Kettle, over a solid bed of charcoal, with apple wood placed on the coals. Season the meat with salt and pepper, or substitute Adolph's meat tenderizer for the salt,a and stab thoroughly with a fork. Place on the grill and cover. Close all vents half way and cook to a meat temperature of 150' F. Remove and let rest for 5 to 10 minutes. Serve with sweet potatoes and a bright green veggie. Again, I like to top these with a good apple sauce, though I have used a dry rub with these.
Enjoy.
Seeeeeeya; Goodweed of the North