The secret to making jam without commercial pectin is to add lemon juice and a cut-up apple to your jam pot (and you may need to cook it a bit longer). Both fruits have naturally-occurring pectin, which serves to help solidify your jam. For example, proportions for a small small batch of strawberry jam could be: three cups of berries,1 1/2 cups sugar (or honey), juice from half a lemon and half a cut-up apple.
How do you know when a peach is ripe? My mom grew up in the south, making her a peach expert. She taught us to only eat a peach when you can smell it, to ripen them quickly by sticking them in a brown paper bag, and to store ripened peaches in the fridge until ready to eat.