A good combo is 1st to get a strong Pokemon, preferably a lv 100 one and teach it false swipe, to guarantee thy have 1 health point remaining. 2nd . Now that they have 1 hp. Get a Pokemon to paralyze it, like with glare or thunder wave. And 3rd get a fast Pokemon with mean look, and use it and taunt so they have no chance of escaping, use mean look and then taunt if they have roar. 4th after that just spam ultra balls and timer balls. A even better one is to try to catch them at night and use a dusk ball :3 they're not that difficult to capture as they seem. :)