First of all, it takes courage to ask to be mentored in this racing game.
I had similar advice from a person who solely lived off the punt.
I asked the same question...the answer was not handed out on a platter.

The first suggestion was to go to the race meetings for 2 years and do not put on a single bet. Observe and take certain notes.

Due to my personal circumstances at the time this was not always convenient, and he stopped suggesting the next thing until I completed my 2 year stint.
Have since lost contact.

If I was to mentor, all I can say is do a 2 year stint, observe and take certain notes.

"Reverse Engineering" as in why are the prices that price and why do they change when they change. And why the pre-post is one price and the openers are another price and what makes those prices change.
What is the "best" pre-post prices to follow will become your personal choice. But I stick to one source and compare with others occasionally.

From there you may or may not "get it", that is entirely up to you.

If you ever hit a "mental brick wall" and wish you had a hammer to smash all your systems, and you don't at the last minute...good.
I hope you smash the delusion instead and have faith in your punting method/s.

And that is as far as I can take anyone, because by then, ( it's a journey) ya be on ya own feet as far as making race selections within a percentage of profit, and will know if it's right for you.