Without writing CHAPTERS on it I'll offer a few notes.
Risk/reward ratios apply, i.e. for high rewards expect high risk.
Example 1) Lotteries have BIG reward, low probability of winning, your $1 , $5 or $10 ticket is a near certain complete loss.
Example 2) Coin flip, head/tails usually low stakes, about even probability.
Wandering a little into the mid ground where I have had a little experience.
Example 3) Horse races.
The favorite will return modest gain IF it wins.
The outsider will return much bigger gains, but has a much lower probability of winning.
So what to do, what to do ?
a) Don't bet, just enjoy the day at the track.
b) Random choice based on LIKING the horse's name - if you know NOTHING you have about an 8 to 1 chance of picking the winner. (Some of my family do exactly this, sometiimes it works other times not))
c) Somewhere down the card there is a risk/return that is about right.
I have done this and on any particular day picked the 2nd favorite in every race.
Other days I have accepted a little more risk in the hopes of a little more return and gone for 3rd favorite.
Both have worked - both have not worked.
My bets were $10 to win, no combinations just straight win, that was the first year or two.
I went to $100 and had a few bad days but more good days.
Bottom line I came out ahead, but it was with money that I could have afforded to lose.
On the days that I lost my consolation was that we had a nice day out - an expen$ive day out, but nice.
I just ONCE had an opportunity to use what I thought might be insider knowledge.
I was to move a horse from the track to her winter home at the end of the season.
The owner kept putting it off but finally set a date and I went to the track the day before.
She was entered and (background story, I know why) her starting price was 38:1, I Put $10 on to win.
Surprise SURPRISE ! She won, I collected $380.
OK, the "game" that owners and trainers play is one of entering or scratching.
The owner of THAT horse had been HOLDING her for over a week - basically to enter her against a field that she would have a very good chance against.
Yes, they ALL play this game and we (punters) have little knowledge of what who is considering in their "poker" game behind the scenes.