I'm not that amazing at this game, but if you need help, then you're in the same boat. So I hope I can give you some low skill strats for this high skill game.
I go over all of the major bosses of the game and a few of the sub bosses. I also give out general game tips throughout the whole guide.
The first few fights are me dubbing over a video because my mic wasn't recording :(
0:00 Intro
0:01:02 Gyoubu Oniwa
0:05:46 Talking about skills
0:07:39 Pre Lady Butterfly and explaining posture
0:10:44 Lady Butterfly
0:17:53 Blazing Bull
0:21:52 Armored Warrior
0:24:54 Pre Genichiro/ Ashina Elite Jinsuke Saze
0:29:21 Genichiro Ashina
0:36:38 Folding Screen Monkeys
0:40:21 Snake Eyes and Explaining the Ichimonji Double
0:45:11 Long-arm Centipede Giraffe and Walking to the Guardian Ape
0:50:37 Guardian Ape
1:07:28 Finding the Depths and Shichimen Warrior
1:16:14 Headless Ape
1:24:24 O'Rin of the Water and Corrupted Monk
1:38:00 Great Shinobi Owl (Hardest Boss?)
1:49:55 Emma the Gentle Blade
1:54:45 Isshin Ashina
2:13:06 Owl (Father) (Best Boss?)
2:33:03 True Corrupted Monk
2:41:28 Divine Dragon, I got the last Achievement!
2:48:47 Demon of Hatred, Explanation and Cheese
2:58:09 Final Boss: Genichiro, Way of Tomoe and Isshin, the Sword Saint