I really like about note-taking. I really like note-taking.

"About" would only be needed if you were saying what you like about note-taking straight after e.g. "What I really like about note-taking is...."

I really like about note-taking. I really like note-taking.

I really like about note-taking. I really like note-taking.

I really like about note-taking. I really like note-taking.

You could also say "I like a lot of things about note-taking."

At first, I wanted to remember ideas after reading books. At first, I wanted to remember ideas after reading books.

At first, I wanted to remember ideas after reading books. At first, I wanted to remember ideas after reading books.

At first, I wanted to remember ideamy thoughts after reading books. At first, I wanted to remember my thoughts after reading books.

At first, I wanted to remember my ideas and thoughts after reading books. At first, I wanted to remember my ideas and thoughts after reading books.

Added a few words to provide more context.

MI wrote more and more I wrote,because my way of remembering wasn't good enough. I wrote more and more because my way of remembering wasn't good enough.

I think this is what you wanted to say?

More and more I wrote, my way remembering wasn't good enoughSince I'm not good at remembering things, I end up wrote more and more. Since I'm not good at remembering things, I end up wrote more and more.

More and moreAs I wrote more, my way of remembering wasn't good enough. As I wrote more, my way of remembering wasn't good enough.

MI wrote more and more I wrote,, but my way of remembering still wasn't good enough. I wrote more and more, but my way of remembering still wasn't good enough.

One day, I saw a YouTube video, which was about the second brain. One day, I saw a YouTube video, which was about the second brain.

One day, I saw a video on YouTube, which was about the second brain. One day, I saw a video on YouTube, which was about the second brain.

One day, I saw a YouTube, which was video about the second brain. One day, I saw a YouTube video about the second brain.

One day, I sawwatched a YouTube, which was video about the "second brain." One day, I watched a YouTube video about the "second brain."

Since then, I have written many notes on my note app, index cards and in notebooks and so on. Since then, I have written many notes on my note app, index cards and in notebooks and so on.

Since then, I have written many notes on my note app, index cards and, notebooks and so on. Since then, I have written many notes on my note app, index cards, notebooks and so on.

Since then, I have written many notes on my app, index cards and, notebooks, and so on. Since then, I have written many notes on my app, index cards, notebooks, and so on.

Since then, I have written many notes on my notes app, on index cards, and on notebooks and so onother things. Since then, I have written many notes on my notes app, on index cards, and on notebooks and other things.

Arranging notes are not familiar to meI'm not used to arranging notes, but it is very helpful to remember many things thanfrom the past. I'm not used to arranging notes, but it is very helpful to remember many things from the past.

If you were to phrase the sentence starting with "Arranging notes.." you would need to use "is" not "are" as notes are plural so it would be "arranging notes is not/isn't (easy for me)..." However, it sounds better to say "I'm not used to arranging notes".

Arranging notes are not familiar to meI'm still not used to arranging notes yet, but it is very helpful to remember many things thanfrom the past. I'm still not used to arranging notes yet, but it is very helpful to remember many things from the past.

Arranging notes areis not familiar to me, but it is very helpful to remember many things thanfrom the past. Arranging notes is not familiar to me, but it is very helpful to remember many things from the past.

Arranging notes areis not familiar to me, but it is very helpful to remember many things than past. Arranging notes is not familiar to me, but it is very helpful to remember many things than past.

You should "is" here, because the subject is the "arrangement" of the notes (which is singular), not the notes specifically. If you were just saying "Notes are not familiar to me," then using "are" would be correct.