OAKLAND — Schooling in the NBA is hard, and second-year Warriors guard Klay Thompson has had his share of merciless lessons.

The Warriors’ 2011 first-round pick from Washington State, Thompson is a willing student, which is why his growth over the first 46 games this season has been evident.

Thompson has the physical tools to excel in the NBA. He’s 6-foot-7 with decent athleticism and a special shooting ability.

But that’s just the beginning. Thompson now is embracing the complex mental side of NBA basketball.

He is being asked to do quite a bit for a player who has played in only 112 NBA games. He was thrown into the fire when the Warriors traded guard Monta Ellis last March, becoming Golden State’s shooting guard of now and the future. From that point, he was no longer a key reserve, and that sped up his development pace.

“You can take him for granted because he doesn’t play like a second-year guy,” Warriors coach Mark Jackson said. “But he’s learning on the job. We’re very pleased and satisfied. It is a process. There are some growing pains. But he’s a guy who wants to watch film, wants to be coached, wants to be great. When you have that mentality, you speed up the process on your own.”

In addition to scoring, Thompson is being asked to help out on the boards. And with swingman Brandon Rush out for the year with a knee injury, Jackson often asks Thompson to be a defensive stopper.

Early on, the result of this workload occasionally left Thompson fuming at himself. No one is harder on Thompson than he is on himself, and that usually meant hours in the gym late at night or obsessive film study.

Thursday against Dallas, after Thompson missed a technical foul free throw, the Warriors coaches had to get his attention and tell him to let it go.

But that fiery competitiveness has played a key role in Thompson’s rising basketball IQ. As does being a basketball junkie.

Save for a movie here and there, all he watches is basketball. NBA games on League Pass. College games, especially his beloved Cougars. Even D-League games, following his brother, Mychel. And that’s on top of film every other day.

“I think I’m a student of the game,” Thompson said. “I try to pick up something from everybody’s game I watch play.”

Any player will tell you how difficult it is to score big consistently in the NBA. Thompson has a powerful weapon — his outside shot — that defenses gear up to stop.

Thompson said his shot selection has gotten better but that it still needs improvement despite his 16.7 scoring average. He said he sometimes relies too much on his jumper even though he has the ability to put the ball on the floor.

Thompson’s game has grown quite a bit, especially at creating separation to get off his shot. He said he’s learned how to use screens to get open. He studies how his backcourt mate, point guard Stephen Curry, gets players to lean one way and uses ball-fakes to get inside. Thompson said he’s added Dirk Nowitzki’s one-foot step-back, which he said “is a great way to get your shot off.”

Perhaps most noticeably, his defensive lapses have been much fewer. He even seems to be over his habit of stepping out of bounds. Thompson said the progress he’s made, especially on defense, motivates him to continue being a sponge.

“I still think my best basketball is way ahead of me,” Thompson said. “I don’t feel like I’ve arrived yet or reached my potential. … I feel like each month I’ve gotten better, so hopefully February is great.”