Good that the heat/air system is over the door and doesn't interfere with your decor too much. It appears the ceiling fixture to the right of the FP might indicate that the dining space is there. Put a sofa in front of the FP and two small accent chairs with it, facing each other over a round glass coffee table. Can you wall mount the TV left of the FP? I think the room is too narrow to put the TV above the FP - you'll strain your neck. If you mount it opposite the FP, a sofa and two chairs could work but will need to be small scale - try apartment-sized seating. The sofa could face the window with the chairs opposite it. You could turn to see the fire or to watch TV. Swivel chairs come in handy in such tight space.

squeakerd - it is really hard to get a perspective on the whole area but if this is part of a much larger area then I feel you need to first decide just what you want as the end result. Do you just want your entire area to be one open plan or do you want to break it down into visually defined areas within the open plan. As you have the area now, I don't feel any cohesiveness between your table and the sideboard, I think I would move the sideboard to the end wall, it looks more like it would belong there, even just by the shape of the room. Definitely a larger rug will define the space better - just be careful of any trip hazard with the door nearby - but before you decide on the rug, consider window dressings and whether you want things plain or introduce some bold patterns and what colours look best in the area. Artwork can go where your sideboard is now, but again think colours and impact of design on the whole area. It is all very well to build a room around one piece, but you need to look at the impact that piece will have on other items and what limitations it could cause. I would suggest you set aside some serious time to look through photos on Houzz, especially if you can find areas similar to yours, till you find what appeals to you, put the photos into your ideas book and use that to build your room. I have found this invaluable in the past and it has saved me many an expensive mistake.

This made me laugh: http://www.theguardian.com/environment/2016/jun/09/seagull-turns-orange-after-falling-into-vat-of-chicken-tikka-masala I couldn't copy the picture, but it's hilarious.

You might paint the walls a bold color you really love, but I would recommend staying away from wallpaper as it is costly and too difficult to change. I agree with another poster that wider trim around the doors would help, and I would suggest that you paint all the trim white and add crown molding and a mop-board along the floor-wall junctures. I love the wood-tone door and would keep it as an accent piece and for contrast. You might add large, framed mirrors to the walls to reflect light and perhaps add a console table with a fairly large lamp. An interesting print area rug also can add pizzazz to this space. If you can use the bold wall color as an accent throughout the house, it will help to tie the entire color scheme together and give your home a unified look. In the offset hallway shown in Photos Two, Three, and Four, I would suggest you place a desk and chair and/or perhaps some bookcases and curio cabinets to make an interesting entrance way that can double as a study or home office. As an alternative, you could place a narrow dining table with leaves that fold down to allow easy traffic through the hallway. Above the table you could display some framed mirrors and, in matching frames, family photos that can serve as conversation starters. When you entertain, the fold-down dining table could be pulled out and/or moved to another room to accommodate your guests.