eztia If you live near a beach or a coast, it will be much easier to integrate these elements into your decor. Not so much if you are in Oklahoma, USA.
Here are some thoughts:
1.) Use natural rather than man-made motifs (shells instead of lighthouses).
2.) Buy bath towels OR hand towels with embroidered or appliqué (shell) design. Use just a tiny amount of decoration in the room.
3.) Use a sturdy real shell on the countertop for holding a dry toiletry (such as cotton swabs).
4.) Choose a single beach/coastal item for display. Perhaps a single sand dollar in a shadow box frame.
5.) If you have collected items from a beach, you could make a shadowbox collage, and it would be more meaningful.
6.) You might choose sea birds such as a sandpiper instead of found objects. Perhaps a small sculpture on the countertop.
7.) A photo of a sea animal, especially if you are the photographer. A sea otter, seal, starfish...
8.) An enlarged photo of a tide pool, perhaps printed on a stretched canvas. Extra points if you are the photographer.
9.) Perhaps using some color of blue to represent the sky or sea would be welcome in your room. Use cooler colors of blue if the room gets hot. Use a more aqua shade if the room is cool or does not get natural light.
What are your thoughts?

eztia @gspeanut. Are you there? Hello?