I have been playing the horses for 6 years and this game is not simple for me... (english is not my primary language, then my writing could not be as good as it should be)
I have an 8% rebate on exotics and 3% on WPS. Still difficult to make money on the long term. A lot of discipline and patience is needed to master the game, plus good handicapping skills.
One of my rules are never play a favorite, and those are very tempting when you are in losing trend.
Jose