How to divide tall shelves for more storage?

There was a big open area above our built in oven that I asked hubs to make better for storage by rearranging the shelf and adding another one. He used some scrap lumber we have.

Please note that the cabinet is solid 3/4" wood as are the shelves and braces...no sagging...all sturdy wood, not plyboard. If you have composite shelves, you may not be able to do this and may have to put in a wire stackable unit.

Make sure your screws are not too long so as to go all the way through. Gluing as well as screwing these in will help hold them.

And I use these for my rubbermaid and Ziplock to go containers in bins!

Of course you can make yours as finished out as you wish.

You can buy metal "L" brackets. Have a shelf cut to size and place on the installed brackets. Easy peasy. Another way is to get a 1 x 1 board, cut it to the size of the sides and back. Install it around the 3 sides of the cabinet and place a cut-to-size shelf on that.

You could add wood supports on the side and the back of the cabinet, and put a shelf on top of that. At Lowe's in the pre-cut wood department they have 1/4' thickness of wood and 1/2" depending on how much the shelf is going to support.

All you have to do is drill holes and push these in, 4 per shelf, 2 on each side

https://www.amazon.com/Shelf-Support-Bracket-Style-Nickel-25/dp/B0037MIFUA/ref=lp_517826_1_10?s=hardware&ie=UTF8&qid=1540733580&sr=1-10

Thank you everyone. These are very helpful suggestions. I think I will try the brackets and see if that works, then I'll try the carpentry suggestions.