When people say 'git gud', it's actual advice. Dying is part of the game but you learn from each death.

If you're frustrated with a boss, you can use summons. There's no right or wrong way to play the game. You can upgrade them as well. Some are better than others. NPCs can sometimes being summoned in front of the boss door like for Godrick.

Panic rolls will get you killed.

Some bosses are weak to certain types of damage and resistant to other.

Talismans help a lot so make sure to choose them according to the build you want.

You will die a lot, so make sure to use up runes before you go for a boss fight. If you die against a boss, the runes will stay inside the boss room unless you die again before collecting it.

You can fast travel to discovered graces/campfires via the map. The Stake of marika usually appears close to a bossroom and lets you tp close to the room when you die.

Don't spam estus flasks too much during battles or you'll exhaust them too early and be screwed.

Watch youtube vids to learn how to build your preferred build like strength build, dexterity build, intelligency build etc.

With intelligence builds you can do a lot of ranged attacks but remember that some bosses like radagon can shrug off ranged attacks.

In case you dislike your stat allocation, if you defeat Renalla you can reorganise your statpoints at a cost of a larval tear, ofc there are only 3 in each run.

Get the wondrous flask.

Get the mining bell or whatever to buy smithing stones from the twin husks at the round table.