This is such a simple little tip that I cannot believe I overlooked for so long!
Quick Entry in OmniFocus
Now I'm sure you seasoned OmniFocus 2 users know all about the Quick Entry feature. Open up Preferences and on the General tab, you can choose a Quick Entry Shortcut key combination. As you can see, I use ctrl, alt and space and this presents the Quick Entry window for adding tasks to your inbox as they come to mind, in true GTD style.
Historically, I would invoke the shortcut, enter my task/idea and then press Enter when complete, at which point the window would close. If I had multiple ideas, I'd have to invoke the shortcut again before typing. A bit of a pain if ideas kept coming in a short space of time.
What I failed to realise, however, was that if I had pressed ⬆+ ↵ after my first idea, rather than just the ↵ key, I could add tasks to my heart's content.
Sometimes, I can be really dumb. Not always, just sometimes.