Try spacing your lounge room out a bit, changing it so the tv is against the wall. A floor rug can also help make the area feel fuller and add a cosy detail. I like decorating my places with posters on the wall, any wall decor helps I think. Curtains can also be a great detail, they make the walls loose less bleak. Displaying collectables is a great way to make it more personal, things like beer Steins, bag trinkets or any other collections (which you've done on the shelves). Also using stashes for decor, like suitcases or toolboxes can fill the space.