`C-c C-l` is also useful if you're linking to files (org or other). You can use `M-x org-store-link` in the link destination, and a subsequent `C-c C-l` will let you add that link easily.
I use orgmode for all my notes and productivity system and can't remember ever writing a link manually in orgmode. These two shortcuts are essential. I assume similar exist for markdown and I need to learn them.