Depends on the country but in the US credit rating is king. I knownpeople who moved to US who are taking a loan for a car and immediately pay it off just to build a score.
That's kind of a poor strategy. Open accounts, utilization, and average age of credit are the largest factors. Paying off a loan immediately may actually lower your score.
According to CreditKarma, getting "excellent" on the number of open accounts factor means having 21 or more open accounts. Assuming you have 4 cc, 2 student loans, 1 car loan and 1 mortgage you would still be in the "poor" category. I don't think I'll ever get out of the "very poor" category (0-5).
That's... insane to me. Right now I have 2 open accounts. 1 CC (that I pay off every month so no interest) and my Mortgage. I don't even have a car payment right now. Yet my credit rating is top like... 4%? Mind I've had that credit card for almost 2 decades at this point.
Shop around for credit cards more often. You can find deals where they will pay you $400 just for using their card for 3 months. A pair of southwest cards timed to get a companion pass can be worth close to $4000 if you do it right.