This is a cute way to decorate with shelves for a kids room https://familyfocusblog.com/diy-tree-bookshelf-tutorial/
Thanks so much for your kind words!
Do you mean you need shelves for decorative items or do you mean you have shelves and don't know what to put on them? 1) books, 2) shells or other things from nature 3) any kind of collection, animal figures, candlesticks, china, clocks, boxes etc.
here are some tips for arranging items on shelves https://www.housebyhoff.com/2018/04/how-to-style-open-shelves-3-tips-for-an-uncluttered-look/