1. Walk fast.
2. Hold a clipboard.
Holding a clipboard makes you look efficient as fuck. Fact. If you hold a clipboard you will look like you're on top of a long-ass list of tasks that you will accomplish, even if that list in your mind actually consists of "waiting for lunch" and "avoiding responsibilities".
3. Pretend to be looking for something.
4. Ask your boss if they've seen one of your co-workers.
5. Be fidgety, all the time.
6. Sigh as if there aren't enough hours in the day.
Busy people never have enough hours in the day, and they hate it. If you want to look busy and be convincing about it, throw an exaggerated, exasperated sigh out within earshot of your co-workers about once an hour so they know how hard you're working and how much you wish you could be doing more, if only there were more time.
7. Pick things up.
Pick stock up, pick papers up, pick pens up. Literally just pick up objects. Picking up an object suggests you're going to do something with said object. Maybe you'll write a list, maybe you'll put some stock out, maybe you'll complete a very important memo. Either way, the possibilities are endless and you'll look busy as fuck.
8. Carry a small pile of items across the store.
9. Literally always be carrying something.
Again, this is similar to #8, but really, it cannot be stressed enough how imperative it is to always be holding or carrying something. Carrying something implies a purpose, so your boss will be far less likely to question your actions.
10. Place items down, very deliberately.
11. Make "tut-tut" noises as if you are mildly displeased.
Tut-tutting is an A+ way to show that something is mildly askew, and gives your boss the impression that you know the high standards that are expected, that you're disappointed to see something isn't living up to expectation, and gives the illusion that you will fix said discrepancy at your earliest convenience. If only you weren't so busy, ya know?
Here's a pro-tip, you guys. If no one can see you, no one can know that you're not doing any work. It's imperative, however, that you remember what we talked about earlier: cameras. Hide. In. A. Blind. Zone. People. You have been warned.
13. Reorganise something totally mundane, like a box of stickers.
That GIF? That's your boss, being impressed by the excellent and thorough job that you're doing. A+ work, buddy, keep it up.