One place to start might be to work out what bad strategies you had in the past. Was your problem that you can't pick winning horses or was it the lack of discipline? Did you get behind on the day, throw your possible winning strategies out the window and chase favorites to try and get back in front?
Be honest and tell us how you think you did so badly, that will (in my opinion) be a good place to start building.
If you've got bad habits which you're likely to carry forward probably no winning system we can suggest will help you.

KV