Once you’ve used Gmail for awhile, hunting down a particular email can seem like a gnarly round of Where’s Waldo? — you know what you’re looking for, but finding it is another story entirely.Labels and stars can sometimes do the trick; other times, you need something a little more, well, advanced. That’s where Gmail’s advanced search options come in. Check out these 10 tips for advanced Gmail search functions that’ll make hounding old emails a breeze. Mad Men fans, keep a look out for example searches that would come in handy at a modern-day Sterling Cooper Draper Pryce.