Destroyed my credit as a naive college freshman; now feeling the heat as a wiser (probably still naive) senior?

My fiances credit use to be 495. HORRIBLE all due to college debt. Hes made it go up to 580 in a short period of time by paying of his debt AND looking into HSBC bank credit cards. You put in two hundred dollars minimum and thats your "credit limit" you can put in more in the card to make it look like you have a larger limit. He put in 5000 and never really used the card. If he did he put the money back in. After 6 months to 8 months he applied to 2 more cards with actual limits, got approved and NEVER USED the cards. He also found an apartment complex who takes bad credit but reports on your credit and is never late on rent. He looks on paper like he makes his payments always on the past two years and has steady income with nothing in collections. He just got approved for a home loan with the help on the VA and that will help his score now too. It wont be a quick fix but you can repair it in 5 years or so. Sorry that it happened to you too.