Prioritize traffic by TCP/UDP Port number?

I recently bought a Mikrotik router knowing that it will improve my game latency. Upon configuring the basics of the router, now I want to configure the router to prioritize certain ports and less prioritize ports 80 & 443 and I don’t know why. Can someone teach me the basics.

Hardware: Mikrotik RouterBoard RB941-2nd(hAP lite)

You should start here:
http://wiki.mikrotik.com/wiki/Traffic_Priortization,_RouterOS_QoS_Implemetation

You can mark the traffic for your gaming console type (i.e. PlayStation, XBox,etc) with mangle rules and then assign it to a priority bucket.