Your walls and painted woodwork is a beautiful start to your coastal room. If you to to overstock.com and in the search bar type "coastal rugs" you will find a nice collection. The sisal rug and dark ottoman in your room doesn't do it justice. Continue with blues, whites, grays, yellows.

Sorry for the quality of the photo. This is from overstock.com and it is very coastal with a variety of colors to use in your scheme.

Great start so far! Don't forget to incorporate deep, cushy furniture you can all enjoy together. This room will be your haven. Make sure you select textiles that are easy to maintain.

Paint the wall behind your bookshelves a beautiful antique aqua or teal. This will be a beautiful pop of color without overwhelming color to your beautiful neutral room. Then a complimenting rug and throw pillows would complete the look. Add texture to the items on your shelves with some natural material accessories from the sea: coral, shells, drift wood, star fish, etc. These would look gorgeous with some antique mirrored accent pieces against this paint color.

I have some sofa cushions cover designs which I think looks good.

https://www.etsy.com/listing/224770292/throw-pillow-covers-16x16-applique

https://www.etsy.com/listing/224767190/applique-pillow-peach-pillow-cover

Hi, below are a couple of photos that may help with inspiration/ideas.

To start, I would suggest to figure out your furniture arrangement and main furniture pieces. Something similar to the photos below is what I visualize in your space.....with 1-2 sofas and 2 chairs......a sofa facing the fireplace/TV wall, 2 chairs in front of the (bay?) window wall and perhaps another sofa right across and facing the windows (unless you need more floor space for the kids). An L-shaped sectional instead of the 2 sofas could work here too.

Also, if you can post more photos of the room (of all 4 "walls") that would help with more suggestions.

PS I think the style and color of your current rug would work well for a room with a coastal vibe. Its size looks like it should work too. Do you prefer a rug with more color or pattern? IMO, I would keep it for now and see how it works out with your new furniture first (unless it's just due for a change because of wear and tear).

Other half of room

Hi, just thought I would mention....since you have kids and looking to create a coastal feel in your space.....which many times means lighter (even white) fabric on furniture.....you will probably enjoy viewing this video diary of a beach house makeover. It was for a family with 2 kids....and most (maybe all?) of their upholstered pieces was done in Sunbrella.

What I'm posting below is just the first of the many episodes of this video diary. But I think you'll find it entertaining enough to watch all of the episodes (eventually).

And, even if you don't choose to use Sunbrella fabrics, I think you'll find a lot of inspiration and ideas in these episodes for what you're trying to achieve.

Btw, the first "inspiration" picture I posted in my last post is of the main family room in the beach house featured here.

If you click on my name and go to my Ideabooks, you’ll find one I named 'Coastal LR’ where I saved a bunch of furniture, fabrics, etc as inspiration for your room. Let me know what you think or if you have any questions.

Not only will watching the tv be easier with deco's suggestion, but it seems like the conversation area would be cozied up and tighter, too.

Cluster your furniture around the rug......I think it would be difficult for a group to converse, play with kids or watch TV.....

You have all of the makings of a lovely costal room - just add some decorative touches other posters have recommended. My only major suggestion for this space is that all of the furniture is pushed up against the walls. This room is large and the furniture should be grouped in the center with space around it on all sides.

Ideas for ding room and entry please!

Paint the backs of the builtin bookcases a soft grayed awu

Sorry about that post. I think it would give a pretty backdrop for your books and decorative items to paint the backs of the builtin bookcases a grayed aqua and carry that same shade into upholstery fabric for two comfortable chairs to use in your conversation area. Aquas always speak to a coastal feel and look beautiful with gray.