For internal links, I use the
[[wiki links]] style. This is the default option and I find it’s just faster when I’m typing and am pretty sure there’s a note I want to link to. And if I’m wrong, it’s one click to make that note.
For external links, I have a strong preference for reference-style links in my notes. Given that I spend so much time in Edit Mode, I find this keeps the notes more readable.
I use named references, usually only one word, and stay away from numbers. Why? Because I’m always re-ordering them.
Obsidian renders the references in smaller text, making them easy to ignore most of the time. But when you need them, they are easy to find.
I also like putting them at the bottom of the current note, below a Horizontal Rule, where they are out of the way. I have experimented with putting all of the references at the top of the file, but for now, I keep them at the bottom.