Universal tip: install the mod that gives you a prism spiribird at the start of every hunt so you don't need to waste time tracking the birds down.

As for the longsword itself, any idea what specifically is tripping you up? As someone with some experience in Rise (made it to very early master rank) and a decent amount of experience in World (made it to, but never beat, Alatreon), I found that it mostly worked the same. The differences I encountered were that the helmbreaker finisher now costs a wirebug, and that you have some new moves in the form of switch skills (mostly personal preference) and a new stationary counter that costs two wirebugs.