Hello,
There are multiple ways you can attempt to bypass proxy servers. But bypassing proxy servers will be against your schools or works places rules. You can use the browser method which is finding html proxy websites which will load a requested website on there server and then send it to your browser.
Another method which is more advanced but better is by using a technique called SSH tunnelling, basically you use a ssh client such as putty to connect to a remote server, then you send all your traffic through this External server.
The good thing about ssl tunnelling is that you can basically how no restrictions, if you no what you are doing you can set it up so you can use any application you want.
The first thing you will need to do for ssh tunnelling is fine a server, you can purchase VPS for about £5 from which place http://gbservers.co.uk, then all you need to do is connect to your remote server using putty. You can find lots of guides online on how to setup putty to forward traffic.
If its like my college they have blocked the defualt port which ssh operates on, to get past this i setup multiple ports for ssh on my server and found out that ports 443 are normally open and can be used for ssh connections normally. Port 443 is used for SSL connections but you wont really need ssl connections at school.