Well, the speeds will come from either your carrier/service provider and the data plan you have with them, or, if using WiFi, whatever speed that WiFi connection is getting.
In the case of the one through a data plan, there isn't much you can do. In regard to a WiFi connection, you can try rebooting the router/modem that you are connecting to (if it is your own). You can also contact your service provider/carrier if you aren't getting the speed you should be getting from the router/modem. Otherwise if it is public WiFi or something similar (where you don't have access to the modem/router) then there isn't much you can do there either.
Lastly, take note, the more apps you are running that access your data or WiFi connection, even if you aren't actively using them at the time, the more your speed will decrease. So you may want to close down (make sure they aren't running even in the background) any apps you aren't using.