You can buy a Ferrari and while connecting to the net at 3g, drive really fast in the direction of the nearest tower so the signal can get there faster.
I've heard that you need if you remove your battery, take out the sim card, switch it back on, enable WiFi, Bluetooth, GPS and put the radio on for an hour, something in the circuit board changes and it enables 4G.
There are guides on the internet where you can put some silicone on a certain corner of your phone (depending on model) and heat it at low heat in an oven (100'C).
What phone model do you have, then I can search for a guide?