Building Credit ?

My credit score is at a 490 I’ve had 2 credit cards with capital one which I am in debt and need to owe them. If I’m able to pay it all my score will boost a lot more vs paying some off every month. I’m really hoping that I’ll be able to gain my score back in the 600+. I also use credit karma to keep track of my scores and other details. My plan is to pay off my debt and apply for a new credit card through credit karma based on what they’d recommend what’s best for me then work my way on up.