Two simple tips found in the same day!
Wireless is weak in my office so I want to get the MBP to prefer the wired connection. Actually simple but not if you’ve never done it before:
You can set the priority of your network interfaces with a Mac which would allow the use of the best connection available.
Go to: System Preferences –> Network and click the configuration tab towards the bottom as displayed below. Select Set Service Order…
Then change the order and press “OK”!
Source: Network settings – Prioritize network connections in Mac OS X – Hudgins Wiki