Its a lot easier said than done. Eventually they figure out that switching between low ball and high ball doesn't work so they will mix it up and now I have to guess while trying to get in and its even worse for ermac/reptile. Idk if its lack of good kenshis on xbox but I haven't had trouble with him yet. The worst is sub though if they get me out once I can rarely win. Trading with ice balls used to somewhat work because they couldn't get full combos and with online lag I can get away with it full screen but now with the 10 extra frames on the freeze trading isn't an option. My other two mains are mileena and kabal and mileena is terrible against sub and IAF are a pain in the ass to do online so if I go against a good sub life gets a lot harder.
Trust me I know it is; I still do ex shadow at the wrong times. I'm not great at all, I know how you're supposed to play, I know the philosophy, the strategy, but I can't implement it into my own gameplay well.
Don't bother trading with sub, it's not worth it especially now, and I don't recommend throwing a forceball except at midscreen or further on their wakeup(they were knocked down) on say shadow kick. If you can successfully, more power to you, show me how to do it right lol. But as of now I don't think it's the best idea. It's a bad projectile. You
can however catch a levitating sindel, trying to fake you out with a high forceball for a free 8 % and a dash or two.