I like topics like this, but unfortunately the first person to reply has usually said just about all there is to say as the strategy is pretty much the same for beating Emerald no matter where you go. Just abuse KOTR and keep miming it. Alternately you could do that with Cloud's Omnislash, but it puts you at a bit of a disadvantage as Cloud is the only one that can use it.
Here are a couple strategy's for you. There's bound to be more on other FFVII fan websites and at GameFAQ's you just have to do a little searching. As I said before most of the information will be relatively the same.
Actually I should mention those two strategy's are a bit different than the one everyone seems to use which is just summon KOTR and keep miming it, while doing what you can to keep your members alive. Having the Pheonix summon, or at least a mastered a Life Materia paried with Final Attack will save your ass.