How do horse race gamblers pick the horse they think will win?

In 1990’s I went to the horse races. I went to horse stalls, with a plan to see the horses in person. Number #8 reared up, and was amped. So I picked it. I bet $2 and it won first place and I won $8.

Also I had a magazine that you can buy listed the rankings of all of the horses, and can decide from it.

I think that the odds are determined by how much money is bet on each horse.

@RedDeerGuy1 describes pari-mutuel betting: odds are determined based on how people bet.

Like @RedDeerGuy1 I went to the paddock before a race and watched which horse took a long piss or a big dump. That was the lightest one and a good bet to show.

I think they go by the history of the horse and it’s breading. What horse (family) it came from and how many races it won, placed or showed.

Some people go by a feeling, or the horse’s name, something they feel is lucky or meaningful in some obscure way. Some look at the odds. Some look at who the jockey is. Some look at the horse’s father and mother (bloodline) and whether there were any winners there, and the horse himself or herself, what their record of wins and losses are, some horses do better on a loose track, some do better with longer races, some do better with shorter races (come out of the gate quick, but tire in a longer race). All kinds of things.

Not well. That’s why it’s gambling. If there was a system that worked, then the betters wouldn’t be gambling, they’d be investing. And they’d run the track into bankruptcy. The entire business model relies on them NOT having a successful system.

I heard somewhere that you can do fairly well by betting on the favored horse to show.

The bookies are already ahead of you. They pick the horse they think will win and calculate the odds accordingly. Personally, I did quite well for a time by picking horses with my favourite colour in their name.

If there was a way to reliably pick the winner, you would get kicked out for doing it.
See Card Counting in Casinos.

Of course it changes if it rains and the track is slop. His father was a mudder, his mother was a mudder.

https://youtu.be/BAIlVCStp3c A lot of factors involved : )

Oh man. Thanks jellies for all the cool answers. Especially the video clips! :)