Annotating Books | Should I Try It?

I recently watched a BookTube video all about annotating books, via the Little Book Owl, and it got me thinking about how I have in the past kept my thoughts organized or tabbed parts I liked in books and whether or not I could actually bring myself to writing in a book or highlighting passages.

In the past, I had highlighted in text books for college courses when studying, but I have never written or used a highlighter in a book. A few years ago, I actually wanted to try my hand at it, but somehow I didn't get the chance. The local library had a program called Graffiti in the Margins where you could borrow a book and highlight, write, etc in the margins of the book and then they would be added to by more readers. It sounded so fun, I wonder if it's still a program or not? 

EDIT: They no longer offer it. 

I normally just put post it notes in books that I'm reading and I want to remember a quote or passage. But I've gotten away from this lately. 

So now I'm torn about even attempting this or using a combination. Perhaps sticky tabs for now and maybe down the road I could try writing in an ARC or a copy of a book I know I'll reread again and again so that I can put updated annotations each time I read it? Think: Harry Potter? Or a 5 star fave?

So my questions are: Do you annotate your books? What method do you use most?

What book would you be willing to try it with first?