Just crossed the $4,000 threshold for my Chase Sapphire card, and did so in less than 2 months! Making almost $700 in travel points and no debts! Paid the balance every single day.
Three things helped:
1. We went on an already planned vacation. (Got double points on hotels, rental car, and dining.)
2. My parents paid some bills using my card and paid us back.
3. We used the card to pay for everything else we would ordinarily buy.