I've got the Lynels down to where I rarely get hit, especially the ones that wield swords. I have yet to encounter one with a hammer though. Managed to get a Savage Lynel Shield with 81 defense, which is my best haul yet.
Melee attack: Jump back
Charge with weapon: Jump back
Charge without weapon: Jump to the side
Fireball attack: Sprint to the side and after the third shot, shoot him in the head to stagger him. When staggered, you can run up and mount them to get a couple free shots in.
AoE Explosion Attack: Just run away and then run back in. Never let a Lynel pull out his bow.
I think the Lynels that use Spears have a leaping attack that you just need to run away from because it has an AoE effect as they land.