I want our beach cottage to have an old, rustic, beachy look.

https://www.pinterest.com/explore/rustic-beach-decor/?lp=true

Are you looking to completely remodel? Or trying to just aesthetically change what the existing materials look like? What you have now is very clean and clear. The pre-finished Oak flooring can be sanded and stained if you want to change your flooring, the same goes for the wood paneling. It depends on how light or dark you want to go. I think that sanding the paneling down, and maybe a cool brown stain and then a white wash would look both beachy and rustic.

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If you don't want to remove the wainscoting, used a distressed look. Paint first in a blue-grey. Then paint white. The white you chose should have a blue base. Sand on edges of boards so that the layers show, sometimes all the way down to the wood. Paint the walls in a pastel blue. Use other distressed accessories in similar tones and cover any furniture with white slip covers. Paint all your pictures frames in shades of blue and whites and grey. Good luck.

Hello, Unicorn spit has a weathered glaze and you could add a little Zia here and there. I am going to add the site for the unicorn spit and a pic of what I mean. Then you could match your curtains to the Zia color.

http://eclecticproducts.com/products/unicorn-spit-gel-stain/unicornspit-gel-stain.html

Toss the window covering, replace with something breezier. Is there driftwood on your beach? Maybe replace the frames around the pictures with something more 'beat up'.?

The colors in the wainscoting and flooring are definitely at odds with each other. Maybe just changing the color of the wainscoting will be enough to give you the more rustic look.

Work with the floor - way too much wk. paint ur wainscoting white, walls a pale gray, frames white to b consistent, get some white matchstick blinds (they r inexpensive) then simple brushed nickel rods & white tab curtains, cut off tabs use brushed nickel clip rings & cheery green runner (rug) beachy look w/o screaming BEACH!! Have fun!!

Maybe a little redder brown, but not to dark. That would take you into 'rustic barn' which isn't what you wanted. Unless your typo "rusty" was more what you want?

Maybe just a white wash over the blonde? Start easy first...get another rug for the area in a bluer color, bring the water theme inside. Or even easier, take the rugs out and toss down a blue sheet/fabric piece/roll of paper. Even just a simple change can be all you need.