Like Izzy Iz said, it's really crucial to mix up your options. One thing you might want to try to do, but not too often unless your opponent repeatedly falls for it, is just hit out, jump, fair, dolphin slash to get back on the edge. Yeah, this is also partially dependent on whether or not your opponent will have enough hitstun from the fair for you to actually get back, but still. Also, don't always get back up immediately. Sometimes hitting out and then just jumping back onto the ledge to confuse your opponent is a good option. Just don't get knocked off of the edge by a surprise dsmash/dtilt. Also, if your opponent messes up with one little thing, try to take advantage of the chance to get back on stage and get back into the neutral game. Punish if you can, but in that situation, it could be tough.