My backyard floods in certain areas, what can I do to fix this?

I had a French drain put in a house I owned in NC and that took care of my problem. A ditch is the only other way I know. Good luck.

Improve the drainage - Fork the area

if it's simply some 'low' areas and they absorb within 24 hrs, a load or two of top soil to level it out - reseed

Gutters help a lot. If your house is lower than the yard behind it you will need to divert the water away from the house. to do this dog a 8x8 ditch 2 feet away from the house using the soil you remove to make a small berm just behind the ditch. Compact the soil using a tamper and put sod over the fresh dirt to prevent erosion. the ditch and berm sh extend past the house on both ends to allow water to go around instead of into you home

Or you could plant a water loving flower garden? They are used a lot for water spots.

A dry creek is an option. Beautiful and functional. Link attached. Hope this helps. https://www.google.com/search?q=how%20to%20make%20a%20dry%20creek%20bed%20for%20drainage

I had the same problem when I moved in. I installed a french drain. No problems since.