Walk fast on the floor.
Look annoyed and a bit tired
Walk fast
Book a call with a fake account and sit in the conf room, act serious if anybody walks in
Keep 2-3 empty coffee mugs around yourself
Eat food at workstation
Take up a marker and start drawing flowcharts for anything
Go to junior's desk and talk to them about their job in the name of mentorship.
Block time for a presentation and then last minute cancel for some urgent client call/ jira issue (you will really score some points for it but you cannot repeat it)
Stand up and take a walk, with hands behind your back looking like you're in deep thought, ask random questions to people around
Email progress to your boss at irregular timings or weekends.