New to game, tips for Legend and higher?

Just started last weekend with some of my friends who played this a while back and we've worked out way up to champion difficulty and are pretty consistent (a few mistakes and loses here and there) and want to move up to legend and eventually cataclysm. I haven't really read up much on builds or meta but have heard from friends that you need to basically min max for cataclysm. Should I be looking up builds for legend or does generally most weapons/classes work. I'm a handmaiden/slayer main.