Some blues would be pretty - my fav pillow sources are Arianna Belle (she has info on her site about #/size of pillows for sectionals which i think would be really helpful) - also Anne Selke and the Etsy shop Pop O Color have great choices -

but i would first start first with A Belle so you know the sizes/shapes you want

https://ariannabelle.com/pages/pillow-size-guide-for-sofas

I would go to HomeGoods, buy possibilities in various appealing colors and test them out. You’ll get a great idea of looks good for further shopping. Return and replace to fine tune. You may find the perfect pillows at a great price too.

I looked on Wayfair. I would get a multitoned blue throw for one end.

These are pillow covers sold on Etsy

If you don't see any you LOVE --let it go! You will know when it's the pillow you want to take home.

@Anne Duke’s suggestion is great, re: trying out pillows. And as mentioned, @Etsy.com is also a nice pillow resource. And definitely go with what you love; it’s your space.

Three or four pillows is all you really need, and maybe a throw. You could do more, but sometimes less ‘is‘ more.

For example: if you are using this fabric - just get two of these made

Add a lumbar

And another pillow in a pattern and or another texture.

Lots of ways you can go. This one below is sort of in similar colorway, etc., as your fabric.

https://www.completely-coastal.com/2018/06/coastal-beach-throw-pillow-covers-makeover-idea.html?m=1

I like your window shades. Are they roller shades?

Yes they are….we scored them on clearance at The Curtain Shop when we built the house! We lucked out b/c they were exactly what we had in mind 😄

Thank you ALL so much…..LOVING these suggestions & will for sure be grabbing up a bunch at Home Goods to trial & narrow down what look I like!!! Will then explore all of the sources you suggested!!!

I can't be anymore coastal, with ocean all around me. If I can make a suggestion, don't do the coastal "stuff", like the anchor and the star fish. That's trying too hard with inexpensive pieces. IMO, it spoils what you have going on. You need art over the sofa and a rug, then find the pillows.

Pull the sectional out a bit from the wall.

Put the end table and lamp at the other end and add a floor lamp...a plant would look great, too.