You can forbid your device from replying to ping, Also change your mac address to a device that is already connected so if they choose to filter mac addresses one of the device they use will be hit offline, check what ports are open.
You can do this with the command:
Make sure your device doesn't have any suspicious port open such as port: 1337 (Never use this port it's obvious)
Don't give your device weird names.
Evade network scanners by setting your IP out of its range. eg: If a network scanner has a range of 192.168.0.255 then set your ip to 192.168.9.10.
A Nice scheme is to make your device look like a printer or fax just download the whole webpage from the real printer (If it supports HTTP or HTTPS) (You can also use iframes)
Then direct all the requests to the real printer in case they test print. (Sometimes you can hide things in plain sight) (Make sure the real printer is always online if its not and your fake page is still up then most likely your cover has been broken.)
Use programming skills if you have any at hand.
Some of these won't be convincing together such as a printer out of the IP range, 2 of the same printers on the same network.