What is the best way to improve an RF cable connection?

The connection on the back of my YouView box seems to be a bit iffy of late. The TV picture will occasionally break up. Sometimes not all channels are available. Very occasionally I get no picture at all. If I unplug and then plugin the RF cable (aerial cable) it comes good.

Is there a trick which will improve what I'm guessing is a loose connection. I'm tempted to give it a squeeze with pliers, or roughen up the cable with some sandpaper. Any other tips?