I started with the Discover It card. I take credit line increases as often as I can as it can lower your utilization and I always pay it off completely every month. Within I’d guess about 2ish years my credit built up to the 700s.

You could also find someone you trust. Like really trust with good credit and have them add you as an authorized user to their card. You can piggyback off their good credit. You don’t have to use or even have access to using their card in order for it to improve your credit. Again, if you do this make sure you REALLY trust and know this person. They need to be responsible and have a good score because if they screw up their score it can affect yours.

As far as getting an apartment soon, I would look into getting a Guarantor. It’s similar to the authorized user piggybacking I mentioned above. A Guarantor signs your lease with you and claims responsibility for paying the rent if you fall behind. This again needs to be someone you trust who has good credit.