Practice
Find designs you like and try to recreate them. Don’t quit when it gets challenging. And when you have created something- put all your feelings aside - ask someone who does this for a living to shred it… Pick apart what you did good.. But more importantly what you did not do well - figure out how to take what you know and improve upon it bit by bit.
Start with small projects - work your way up.
Start thinking with you Heart! Get enrolled in any of the best institution offering Graphic Design course near by your location.
You may browse videos on YouTube, they are handy. Follow designers on Behance, Dribbble, UpLabs etc. Develop your own style of designing.