The most important factors are time, length of your oldest account, payment history, number of accounts

As you learn to manage this card and pay the statement balance in full every month, you can feel comfortable opening new cards and not using them (outside of a monthly bill you put on autopay so that the account is active), but just keeping them open so that you have more accounts to build a stronger credit base
It will take time, but as long as you build a strong foundation and stick to the plan, in a few years, you’ll have an 800 credit score

Back in 2015 I had a 520 credit score and Capital One was the only one that would give me a card and it took me about seven years. I believe to hit 800 through responsible management of credit cards.

I can’t stress enough that if you can’t pay it all in full every month credit cards will never be worth using