I am currently working on rebuilding my credit, which is at 601 right now, and I only have one open account with Capital One. I got pre-approved for an Avant card with a $300 limit. Credit Sesame suggests I could increase my score by around 30 points if I open a new card.
To be honest, I would look into a secured card that graduates, like those from Discover, Citi, or Bank of America. The State Department Credit Union (SDFCU) also has a great secured card that graduates.
The key is to use the Avant card sparingly, keep your credit utilization ratio under 30%, and make all payments by the due date. Checking your credit reports regularly for errors and disputing any inaccuracies can also help. With some patience and good credit habits, you should be able to steadily improve your 601 credit score and work your way into the “good” credit range of 661-780.