The Borussia Dortmund superstar has scored 12 goals in 11 games this season since making his January switch at just 19 years old.
Haarland - who remains a transfer target for United despite the Red Devils being unsuccessful in signing him from RB Leipzig the first time around - was under the stewardship of Solskjaer at Molde.
The Norwegian believes it was during this period in which he learned his trade, and recalls his manager's significant impact during training sessions.
Speaking to Eurosport, Haaland said: “I remember it was frustrating as a young striker, everything goes against you in training.
"I was alone with the keeper and the bar, got crosses from Ole Gunnar, but I missed on every opportunity. I remember Ole then said ‘I think you start this game, so just be ready.’"
Admitting that he was struggling in training, Haaland stated Solskjaer gave him some individual training exercise - and they had a big impact mentally.
"Solskjaer and I did some practice on finishing," he said. "Not just crosses, I remember he taught me some easy rules.
"The first one was one-touch [finishes]; that I don’t use too much power and trying to destroy the goal or the goalie with ball.
"I think that I was thinking about doing that and it was something new that he told me. I trained a bit on that, but without scoring. But at least I had it in my head after that training session.
“He has taught me a lot to be calm, and also be on your toes and come to those situations where the ball is coming. It is then you have the chance to score. He deserves a lot of credit for teaching me that.”