Fortunately, Godrick's attacks are extremely telegraphed and elden ring weapons extremely punishable, and generally slow in movement, which leads to a fairly straightforward fight once you've found the patterns. Additionally, you can summon Nepheli right outside the boss's doors if need help (or a distraction). Here is our general guideline for bosses for beating Godrick:

You should generally stay pretty close to Godrick If you're a melee attacker. His axe sweeps appear to have the most hitbox at the very end, therefore if you can dodge the roll and avoid Godrick you'll usually avoid them and end up in a spot that you can attack. Take note that a majority of these are combination attacks, so make careful to maintain your stamina and hold off until the last attack if you're planning to guard against counter. If you are really unsure it is better to stay away and wait for one his slow overhead slams that are simple to take down.

Another easy to see move is his aerial slam, which he announces by grasping the axe's head using his other hand before throwing himself into the air. Dodge as he comes down and then do a 2-4 hit combo while he is in a position to stand up. Another effective move to be punished is his rolling slam. He'll whip up the air around him, and then roll on the ground before rising into the air and smashing into the ground. You can simply walk up to buy Elden Ring Items him when it is high and he'll swoop right over you, letting you take advantage of back slashes while he recovers.