What should I block and allow through my firewall?

I'm trying to increase my internet speed. I live in a rural area so I have to use mobile broadband. I want to limit internet communication to bare minimum to increase my browsing speed. I just don't know what all the stuff is like core networking, homegroup, etc. I know some stuff but my knowledge is limited when it comes to computers. If there are any other ways I can increase my speed please tell me. Thanks.