In "The Rocking-Horse Winner" by D. H. Lawrence, what does Paul do to try to find luck?

Hester is materialistic. She and her husband do not make enough money to suit the social position they like to live in. There is a constant feeling of anxiety in the house and it is based upon a need (or greed) for more money. Much of this anxiety is perpetuated by Hester. The family is haunted by this notion of needing more money. They even hallucinate and hear the phrase "There must be more money!" 

In a conversation with Hester, Paul asks her why they don't have their own car. Hester says it is because they are poor. She adds that they are poor because her husband has no luck. She tells him that luck brings one money. "It's what causes you to have money. If you're lucky you have money." 

Determined to find luck, Paul goes to ride his rocking-horse. 

And he would slash the horse on the neck with the little whip he had asked Uncle Oscar for. He knew the horse could take him to where there was luck, if only he forced it. So he would mount again and start on his furious ride, hoping at last to get there. 

Somehow, riding the rocking-horse allows Paul to come up with winners of upcoming horse races. Thus, he rides to find luck and this leads to money. With Bassett and Uncle Oscar, Paul bets on the races and wins more and more money. He has the money given to his mother anonymously. The problem is that his mother is insatiable. The more money she receives, the more she wants.