You could put a sectional sofa in the middle of the room, with its back to the door, with the chaise part of the sofa (where the sofa forms a right angle) pushed against the wall to the far right. Then, put a sofa table against the back of the sectional, so that when you walk in the front door you have a little "foyer" area to put keys, mail, etc.

Here is a photo to show what I mean: ignore the wicker chair (don't put a chair there!) and the other elements, just pay attention to the placement of the sofa and the sofa table at its back.

Get a radiator cover like this:

and put your tv/entertainment area to the right of the window and the radiator.

Hope that helps!

Perhaps a good place to start is to consider how you see yourselves using the space. What are the three main jobs it needs to do? (i.e. function as an entry area, seating area for watching tv and chatting, and a dining area). Do all those jobs have equal priority? Based on the answers to those questions you can prioritize the flow through the space. A small dresser or wardrobe by the front door for catching mail/keys/winter items might curtail clutter in the main room, and then perhaps the area on the right of the photo could have a loveseat and chairs for seating, and the space on the left could have the table and chairs re-positioned to be parallel with the windows. The sideboard looks nice and can really anchor a space but it looks a bit cramped in its current location. Perhaps move it into the main space on the right? In a fluid space like this it makes sense to keep the colour palette related (shades of the same family) if not exactly the same. Hope that helps and good luck!

Since your walls have that pretty trim in the middle you can make all of the walls two toned, like this (I would use lighter colors though):