How can I make my fireplace look bigger?

Hi

It is beautiful...

Maybe you could add a ceramic tile backsplash (not the right term) to sides, floor and above it and then add a floating shelf as another mantel is my initial thought. Sketch it out on paper to scale, buy grid paper if you do not have and use 1/4" = 1' and then draw in the tiled area and board to see if that might help.. You could color it etc to get thoughts going.

Maybe try an overmantle, google overmantle diy and you should get a lot of ideas. I wouldn’t paint mahogany, but I’m a purist with wood 99.99%of the time. You can do a lot with trim and shelving

You could put mahogany bookcases on each side of the fireplace. And a second mantle above the fireplace.

https://www.hunker.com/12620083/how-to-make-a-fireplace-opening-bigger

http://www.decorsnob.com/get-inspired-fireplace-makeover-ideas/

https://tatertotsandjello.com/10-fireplace-before-and-after-ideas/

https://www.bhg.com/decorating/fireplace/styles/before-and-after-fireplaces/

You could make a wide trim/frame all the way around it in a colour that matches or is the same as the fireplace is now then make a thick shelf/mantle in a dark stain or colour for above the fireplace, you could also add pillar type "legs" for the shelf or mantle one that goes down either side of the fireplace

I would remove the pictures hung over the mantle. You can do a lot with paint. Not the mantle, but the wall around it. You could draw out a surround pattern on the wall, and by using paint, draw the eye upward. An ombre pattern starting at the baseboard with the darker color and going up the wall to a lighter color would be one way to achieve this. Another way would be to use mirror squares as a frame for the entire mantle up the sides and above it for about 3 or 4 ft.

Could you lift it up on a plinth or make a shelf above existing?