There are lots of threads and commands here, and provide so many useful tips and information; but when I find some information/tips I was looking for, and a while later, I want to read them again, I can’t find it.

I know I can favorite pictures, how about posts and comments? Can I favorite them?

You can't. 

But what you can do is leave a "comment" the keep the thread in your profile. Even some simple comment like "note" "wanna know too" whatever is enough.

Though looking for some tip in a thread can take long depending on how many comments it has.

Or you make a file on your computer where you copy and paste the part/ tip you want to remember and save it under different names on your pc. Something like bc tips, recipes, etc

Thank you so much for your reply,   Julia.

I think I will make some folders on my computer to save those tips.

But you actually have a good point there. Maybe @heath and @jacky can look into it?  I think the best is to email your suggestion to CC.