What’s the best way to do this? I find it a bit tedious to go to the HUD and drag/select; using the inspector and clicking or using the gear menu also seems slow.
Is there a keyboard shortcut? Or maybe just click in the keywords column of the outliner view, as is possible with the labels column…
The ways you describe are the only ways, but remember in the inspector you can hit return to create a new keyword and that as you start typing existing keywords will automatically be suggested.
The purely keyboard way of quickly adding a keyword is:
Ctrl-Opt-Cmd-J + (Repeat if Inspector was closed or on another pane) + Return + “Keyword”
This works also in QuickReference panels and full screen. Again, if the Inspector (Standard, Split, or HUD versions) is already visible and set to Keywords—you just need to use the first shortcut once to move your keyboard focus to the table. If it isn’t open, use it twice, first to reveal and second to focus.
I probably do this 25 to 40 times a day and find it very useful. I don’t bother with the HUD even if the keyword I want already exists, because when you type them in manually, it checks against existing project keywords and auto-completes for you.