All interesting and useful things: http://web.archive.org/web/20151029064531/http://hk-magazine.com/tech/article/hong-kong-life-hacks
(I would also recommend HK Observatory App for weather forecasts / warnings + HKU or CEDARS apps: one of them has webcams to canteens, so you can check queue lengths before you go for lunch.)
If you are below 25, you can apply for the MTR student scheme (ASAP when you arrive -- collect and fill in a form from the Faculty of Engineering general office): http://www.mtr.com.hk/en/customer/tickets/student_travel_scheme.html
If you do not want to wait in a long queue for lunch @ Student Union Restaurant, go to the self-service machine and order a spaghetti or dried octopus with rice (or other ready meal that is served in a box) -- these dishes are given at the sandwich counter which tends not to have a queue.
On Friday afternoons (around 4pm), before iBakery (a coffee / bakery stand before Subway) closes, they try to sell remaining pieces of pastry for a low price (e.g. HKD10 for any 3 pieces).
Sign-up for Octopus AAVS with your HK bank: your Octopus card will be automatically recharged by your credit card. It saves a lot of time and you will almost stop using cash afterwards. :-)