Whats the best way to make a working combolist?

Hey guys I was just wondering I been using slayer leecher alot but I only see to get a few hits sometimes. Im trying to learn how to make good combo lists but I dont think im doing something right. Whether I make 25 k combos or 200k combos they dont seem to be getting hits. for instance I only get a few hits for netflix or spotify and usually they are not premium accounts. If you guys know a better way or can guide me in the right direction it would be much appreciate. Sorry for being such a newb at this but I want to get good enough so I can share some combos and stuff with the forum. I dont want to upload crap here. Thanks in return