I found this - not sure if it works, I haven't tried it yet.
If you want to make money easy do this (in order) with you horses everyday:
-2 lessons
-Train as much as possible
-In the meadow till 20:00
-Feed
-Water
-Carrot
-Groom
-2 Strokes
-Check to see that the energy is above 20% if not give a turnip at this time.
This technique gets you easy money cuz you keep your full paycheck and because the horse is doing lessons and getting paid it pays for its food and then some!
If you want to make money easy do this (in order) with you horses everyday:
-2 lessons
-Train as much as possible
-In the meadow till 20:00
-Feed
-Water
-Carrot
-Groom
-2 Strokes
-Check to see that the energy is above 20% if not give a turnip at this time.
This technique gets you easy money cuz you keep your full paycheck and because the horse is doing lessons and getting paid it pays for its food and then some!