There's no magic answer here to get there in a short amount of time. It simply takes time and one very important ingredient, patience! I'd recommend as you start over with new cards, to pick your new cards wisely, trying to stick with those that best serve your needs and are most likely to grow over time. Avoid adding cards just for the sake of adding cards/accounts, that's for much, much later when you've built up a much longer positive credit history. Another important thing to do, and likely the single most important is to use your cards responsibly.
Treat them as if they're debit cards. Sure, there are times that 0% for xx months is enticing, useful, and can be taken advantage of, but... for the most part keep your utilization low and try to make it a habit to PIF every month. If you can't afford to pay it off in full at the end of the month, think twice about charging it on a card. As you build more trust and history with your lenders, the more they will be willing to entrust you with higher limits and the more likely it becomes that you'll start landing those higher SLs. Best of luck in your rebuild!
