First and foremost, see yourself as a business! Which means you have to get better, you have to be prompt on delivery, you have to understand your process. Concentrate more on client satisfaction over the payment.
Understand the basics of Design: There is a difference between knowing and understanding. You need an in-depth knowledge of the basics.
Know your tools: Understand your tools too. It will help you effectively apply the basics you have learned.
Have your gadgets ready: Your gadgets are as important as your business. Your gadgets can waste your time. And save it too. Get a good system (Check online for minimum system requirements for the software you will be using), get an external storage device, mouse and the likes.
Be ready to learn: Check online for resources. YouTube, Udemy, tutpad.com, lynda.com are examples of places where you can find helpful resources.
Additional tip: Don’t do it for the money, you will know when it is time to start charging and charging well.