Your question is one of my favorites as it allows me to share the credit card system I designed and use that:
1. helped build my credit score up to 815!
2. provides regular cash rewards and statement credits
3. pays me generous welcome bonuses for new credit cards I open
I created a monthly spreadsheet to keep track of the credit cards I have, the charges I have made, and when payment is due. The most important action to take is to PAY CREDIT CARDS ON TIME EVERY MONTH.
It is also crucial to CREATE A BUDGET with each of the CATEGORIES you spend in and stick to it.
There are many more detailed suggestions on my blog. Please refer to posts about credit cards. I love to hear your comments. I hope my system helps you. Blog Posts about Credit Cards
Debt Free Maven