The first two are unnatural. You could say It’s better if you do it or It’d be better if you do/did it (I prefer did here), with no real difference in meaning. You’d better do it (with stress on you’d ) is another way to say it.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Anonymous"It's better for you to do it"."It'd be better for you to do it".I see these as essentially the same, but the second presumes a situation that is more imaginary than real.
Anonymous"You'd better do it".I see this as different in tone. It can even sound threatening in certain contexts.