drayzen, becareful is 100% right.

My advice would be to go back through every bet and record ALL the details including everything to do with horse form etc and look for areas where it strikes the best.

Use an excel spreadsheet and if you need more details on any runner try the horse search option at ozeform.com.
You may be able to find eliminating factors which improve your strike rate.
This can be extremely time consuming, but once it's done; will definately improve your end result with out chasing losses.
Good Luck.