Regarding Get Strong at Tesuji: I was pretty clueless the first time I solved this book, even though I went through Tesuji by Davies beforehand. The thing is, Tesuji has its focus on capturing and connecting Tesujis. Get Strong at Tesuji is a bit broader then that. You have also shape problems, problems to get Sente, even a few endgame problems. So, I'd recommend giving Get Strong at Tesuji a go, especially if you just solved Tesuji by Davies.
Getting problems wrong is good, you can question your own move and your thoughts, which let you believe this was the correct one and so on.
Some quick ideas about your game:

Tenuki is good but I would play a two-space-pincer here (high or low). I feel the left side is more important than the top. This is overly defensive, I think.

With C12 in place, it's now not so easy to get good, solid shape on the left. An idea would be to hold back with a C6-approach and if White takes the corner you extend (check) towards White's stones at the top. This seems a bit more active. But White could also pincer this far approach and things could get dicey : D

I feel like this is the wrong direction with White already having a presence at the bottom.

D6 is the shape move, if I'm not mistaken. White has a good game after the cut.

I think the cut is not important, you can just sacrifice the next stone and get a strong shape in the center. I would play M3 to maybe activate the Aji of Black's bottom stones.

Aji-Keshi?

After playing

and

this a pretty inconsitent because it harms those stones. Maybe still M3?

I'm torn here. I really like to play this at O16. Then on the other hand, I really like to play first in the top left corner, because there White is not so strong and this could give your C8-move more meaning.

Wrong direction. Attaching at O16 makes the right side bigger and swallows the White stone on a large scale. Another possibility (probably better giving the situation) is to play P17 and go for an attack on both stones.

P12 seems to be the only move.

P14 is the right way to capture because it takes away a liberty.

Wrong direction, the corner is bigger.

Still the corner.

Jumping to L16 is the common shape here. Your sequence weakens your top left corner.

Again wrong direction, nothing is attacking this group. But you should attack White's right side stones via O9, also mapping out your right side.