Woof43 would be the man to ask for assistance.
Search him out - on this Forum and wherever.

What he suggests is you run through a database of results.
it must be quite Huge.
Chrome prince I think has that.
Or useless better has a Free website.

you eliminate a certain facter from the results.
then you see whether your profit margin improves
if it does , then there is good possibility that that factor is overbet by the public.
But there must be a basis for your factors.

things to try might be like the bottom weight to win.
topweight to win.
Obvious things that attract Punters.

I delve deep into study of a race.
and i treat each race individually.
My comments are based on common sense rather than any practical knowledge.
But I do know that Woof43 has been making a substantial living from Joe Publics errors.
Like I said , search his posts.
type in say "overbet" in this Forum search panel.
perhaps use advanced to include only woof43