oils can be applied to your weapons to increase there effectiveness some oils are more effective on certain monsters/people. so make sure to prepare.
oils can be bought or crafted with manuscripts

enemys have weaknesses, like how some are flammable, while others arnt. no one strat works for every enemy, so make sure to read up on ingame sources to try and get the edge over your opponent

its better to sidestep a monster than to parry, as if you try to block, it simply will daze you if your opponent is a monster.
side stepping a human is harder, than blocking or parrying there attack.
rolling although useful at times, wont allow you to have a follow up attack, as you cant close the distance, roll only to get out of sticky placement.

side step is a crucial component of fighting, as its easier to sidestep to the side of a monster, than to block/parry. however, its located on left alt for some god awful reason, if you can, rebind it to a mouse button like M4 or m5, if you cant, rebind it to something close and easy to reach.

If you are fighting a ton of enemy at once, keep an eye on both, attacks from the back hurt twice as much, and your enemy will try and take advantage of that, but so can you. if you are in the in between two enemy, roll out and reposition