There's 5 tips I can share with you:
1) Abuse knockdown. Whenever you knock him down, the less shenanigans Junghado tries to pull. He'll try to knee swipe you right after; if you just keep attacking him through the knockdown, he'll be knocked down again(!), giving you good 5 second breathing time.
2) Do not run away from Junghado too far; try to keep a small distance and run circles around him. If you walk away too far and keep trying to escape, he'll dash to you and it will hurt. Edit: There is a sweet spot of medium distance where he doesn't dash to you but likes to use blade call - his most useless ability with a very long cast time.
3) Abuse grapple/phantom grip/etc. Junghado's almost defenseless against it; just use it whenever possible and try to unload as much damage during that time.
4) Abuse Stun/Daze and aerial combos, another source of breathing space and free damage. Edit: Aerials may vary by class, it's a luxury you might not be able to afford if your damage is low.
5) The biggest one. When Junghado hits ~40% health, he starts doing a big AoE charged move, a blast in a circle around him. That one comes from a mile, so you should be able to dodge it. The issue is what comes after it. He'll dash to you and try to do an aerial combo. On top of that, he's immune during that dash, so he often baits a lot of crowd control during that time. If he succeeds, poof, there goes 80% of your health if not more, which means you'll have to start over. You have to iframe(skills tagged as resists status/damage) block/dodge it.
In summary, as you can see, the more you keep Junghado out of the fight, the better, as not only it gives you time for cooldowns, but also gives you free reign to unload dps. With this and saving and ability to block the aerial combo, you should be able to handle it. Good luck for those attempting!