try to determine if you BOTH want to work it out or not, then try to solve it.
also, try to give each other more 'breathing space', you might be in each others face all the time, that gets on nerves. as in you have to 'conform', or think you have to conform if you're always together.
let her know she can do whatever she wants, tell her you having different ideas of what things to do or how to achieve them is just natural, and it shouldn't stop her from doing what she wants.
also, remember to always focus on what started the argument, don't go off on tangents, and NEVER, I mean never bring back something from the past unless it's absolutely relevant. don't say stuff to get to at her, stay as calm as you can be, silence is not good, nothing gets solved that way, and it's too pacifist, but neither is shouting or insulting-'m not implying you do, but everyone does have a limit.
I'd say pause for a second-or more

- when/if an argument develops, then talk, and remember keep your attention on the reason for the argument, and on what the other is saying, try to understand it as it is being said, ask if you don't understand, communication is the key to solving all problems.
say things from your perspective, say 'I' when you describe emotions, that seems like a big duh, but that does make you both aware of each other, that the other might be hurting from what was done/said, also, emotions are ok, no need to be afraid/ashamed of them, and if you're at fault, apologizing is the right thing to do.
one more thing, remember that you Are sisters, and thus are part of a whole, not opposites, and that you don't need to to hit under the belt, rather accept the other person.
I hope that helps, and God willing you'll be well all your days

, ok that was too dramatic, anyway, good luck,,