I dunno, do you like this (from our recently remodeled livingroom w/open entry area? Like Kah says, the easiest place to start is from color -- at least that's what my designer wife did first.

I think this was just brick added to a wall so you should not need anything other than mortar but IMO this looks odd just put in the middle of a wall I would remove it

I have some suggestions if you are thinking budget friendly changes. Make a photo gallery with different size frames and arrange them parallel to the stairs, so you can enjoy each photo as you climb up. And for the area that will be on a level with your upper floor, try some pretty decal that will connect the photo gallery to upper level. And last, if you have budget add some beautiful hanging lights in the stairwell. Also think about repositioning your refrigerator.

Hi Option 1 As suggested by Cornerstone above. This way the TV will be visible from dining too Option 2 Move TV to the corner of the entrance wall, next to the window, placed at 45 degree angle. The L shaped sofa can then go to the diagonally opposite corner. The wall can be a see through book shelf/crockery shelf. This is better as the visitors have some inviting empty space as soon as they walk in instead of a sofa. Option 3 TV in current position, but instead of the TV being mounted on wall, perhaps have an open shelf (like below)