Can you post a photo of the shelves and what you currently have on them?

try to find some bins that fit the shelves -- Ikea, target, and The Container Store have tons. you can hide small items that way. make sure all the bins have the same look (like, the same style and/or color) so it looks tidy. put them on the bottom shelf, and items you do want to look at on the upper shelves (books, decorative items). try finding other hiding places for your lesser used items, such as under the beds, top shelf of closets, etc.

here are the photos of the shelves in question. The brown bookcase is in our living room and the beige shelves are in the dining room by the kitchen

Not sure what you have but if you have a set of matching dishes or nice glass ware or serving pieces, they might look nice displayed on the dining area shelves and it would make them handy to use. Then stash the various bottles in the kitchen cabinet they came out of. 2-3 matching storage baskets would also be a good investment there to give you more hidden storage.

What you see as "outdated", I see as amazing.

That said, do you have a collection of anything? You need items that relate to each other.

And, if the bookcase in the living room isn't necessary, then either move it or store it or sell it on craigslist. It seems to me that you don't use it for books or any other storage.

That little green elephant would look fab in the other shelves...

Perhaps the lower shelves could be for stuff you find useful? Then the decorative stuff on top...

Since I hate to purchase simply because I have to fill a space, I would shop my house, then I would head to the thrift shop for kitschy stuff...

the problem with the white built-ins is that they're really meant for decorative things, not everyday storage. pretty much the only thing I can think is to divide and conquer your stuff. make "themes".

move all drink bottles to one built-in, so it kind of looks like a bar. add drink glasses if you need more stuff in there. for the other bulit-in, put only decorative items, knicknacks (but keep it sparse).

take the cookbooks from the white built-ins and put them in the brown bookcase. you have room. in fact, put more books in the brown case, it looks empty. put the pictures in front of the books, or on top. find bins that will fill the bottom row of that bookcase and fill them with the toys, art supplies. maybe the games can go in a closet?

get rid of that basket of balls, you don't need them (or put them on top of the brown bookcase or a table if you must keep them). if you can, try to find different homes for the other clutter. hide that power strip.

Remove everything from all the shelves-then figure out if you need any of those items. Next only display items that you actually like and fit on the shelf. the upper shelves should be for display not the bottles make one a "bar"- wine or martini glasses with shaker on the upper shelves, with bottels below. Keep items in scale - that dog is just too big.