Don’t play like that, don’t focus on learning to play like that. Might as well play CvS2 EO with the Xbox pad since it takes no skill.
Don’t try to ground attack Gief at all when he’s coming at you with the far 360+K move. Even when it’s not RC’d, the grab is instant as soon as he’s in range and you’ll be grabbed out of practically anything. Jump up every time on reaction instead. It’s a free combo whenever the grab whiffs.
Do poke with safe moves (like Guile d.MK) and look for Gief to be sticking out his laggy d.HP. You can easily hit him afterwards almost always. Throw a poorly ranged fireball or use a laggy move that shouldn’t be used as a poke in the first place and you’re going to eat roll, mash 720 everytime.
Punish all those rolls btw. Don’t try to throw it, because you’ll hardly ever be in range. Use your Sagat d.MK instead. Never let him in on you for free with something stupid like a roll.
Don’t attack or mix-up Gief as he gets up (Sagat dash up jabs or low shorts after a knockdown for example). Even without RC, his 360+P already beats any normal ground move you might use. RC KK move just makes his wake-up even more scrub friendly. If you’re going to attack, you need the attack to be perfectly meaty, and even then, mash 720 will still beat everything you do. Plus the delayed getup C-groove has can throw off your timing as well. Better to always stay out of range whenever Gief gets up. You can get close to fake him, but always move back out of range at the last second (with a dash for example) and make Gief take the bait.
Don’t jump at Gief to try and get in. The PP move (when done deep) is already perfect anti-air. RC KK just makes all anti-air for Gief stupidly easy.
Stay patient and focus on keeping Gief out. Never give up your ground to him (ie. don’t walk back unless you have to), never get desperate to get in with a random roll or jump, punish everything he does (far jump in HP, random roll, spam d.HP mostly),and always stay away from him once he has level 2 or above.
Oh, and if you’re losing to the same guy I think you are, don’t let his furious mashing and randomly yelling out swear words every couple seconds throw you off either.