After years of eating tree-ripened peaches I just haven't been able to eat the ones sold here in the New Mexico desert until this year. Whether they're from the farmer's market or grocery store, organic or conventionally grown, it's like day and night; the same difference between tomatoes that are home grown vs store bought.
When fruits are allowed to tree ripen the sugars and flavors are developed. When picked green for shipping they never go through this stage. It really makes a difference in some fruits like tomatoes and peaches.
Finally, after years of experimenting I found a process that comes close. Start by only buying peaches with a large deep red area. Don't squeeze, that only bruises them, look for color. The deep red occurs on the skin when it's exposed to direct sunlight when its growing.
Don't wash them yet and always treat them gingerly even though they seem like rocks, they bruise and you'll end up cutting those areas away when the peach ripens. Lay them stem side down on a tightly woven cloth.
This needs to be in room temperature away from vents, not in direct sunlight and where they won't be disturbed but where you can check them without handling the peaches.
I don't get any money from this but these worked perfectly--I love these heavy tightly woven organic kitchen towels I found on Amazon amazon.com/gp/product/B0
Give them plenty of room for air to circulate between them. Put a ripe banana with them to speed up the process as it out-gasses ethylene. Double or triple fold a towel for the cover. Gently lay it on top tucking the edges around the peaches or bottom towel.
After 24 hours check them by gently taking the top towel off. A ripe peach is easy to spot, its skin has turned darker and the smell of peachy deliciousness is very strong. When you pick it up it'll probably have a slight give. Keep checking and 'harvesting' every 12 hours.
There are SO many recipes online to explore. Peaches, nature's candy!!
If you live where the peaches don't have to be picked so green to be trucked in so far away, there's an easier method of putting them in a paper bag with a ripened banana.