The inner game can definitely be hard, that is what you'll need to have them stick around. High quality girls know they are high quality and will require high quality stimulation. Lower quality girls won't give a sh!t much the same way you don't give a sh!t, you want sex and they want sex. Higher quality girls will want more than just sex, they want to have a good time overall.
You're tired of just having one night stands, you seek that higher quality. Besides fvcking them you'll go far with enjoying other activities with them, typically things you'd do with a close friend. Basically just treat them as any other good friend and add physical intimacy on top of it.
Some guys think they should treat a girl entirely differently because they're having sex with her. A one night stand is basically just sex and not much else. Friends with benefits is called that because you're exactly that, friends with the addition of sex and physical intimacy. If you know how to be a friend then "friends + sex" shouldn't be hard to do. A relationship is friends with benefits and a higher degree of committment.
Players lack the friends part of it while guys who constantly gets friendzoned lacks the physical part of it. Take the best of both worlds and integrate it, that makes for some quality time.