Generally, it's boring to monitor the log of a proxy server. Unless something happen, I don't think the network admin will have interests to read those stuff.

Anyway, you can follow some guides:

1, Keep a good relationship with the network admin;

2, Don't visit sensitive sites, e.g. sex, political sites.

3, Don't visit non-working-related site when others are besides you.

4, Clear the buffer and history on your local machine everyday.

Good luck.