Cool room! I like the beams and open space. I'd move the sofa further from the wall, and a couple feet forward, in front of the post. It's hard to see how much space you have, but it looks like this would make a cozier TV area. Since you have the strong pattern rug, you might even want to skew the sofa a bit towards the corner. If you can make enough space to walk behind it, the room would "breathe" better. If not, a narrow table the same height as the back of the sofa would be functional. The series of small windows is a bit unfortunate, but if you built shallow (8-9") bookshelves around them on that wall, it would unify things a bit. A bunch of un-matched pillows on the sofa would warm things up. Just make sure they're all great, fun, or interesting, and soft. Use down filler so they crunch into interesting shapes. Finally, a big square coffee table with a distressed wood top, something that feet could go on, would make the space more irresistible, or ottoman that doesn't match the sofa, and some stacks of interesting art books.

Hi, hopefully I've posted the correct sectional below. Check out West Elm for some decent styles that could go with your MCM/beach style. I've posted a few suggestions below for coffee tables. Your side table(s) will probably depend on which coffee table you choose. They don't necessarily have to match....just coordinate with one another.

Do you have a picture of the space?

A regular sofa and one or two accent chairs will give you more options. I like neutral furniture and then add colors with rugs/drapes. Your light fixture is not 'modern' , would you change that as well? Start an idea book by looking at photos of rooms you like: