The really important element is not how long you've been drawing for but how often you do it.The best artists make sure to draw something every day. I however haven't done that and so my growth has been slower than others. It's also about technique. Starting with purely traditional art until you've come to a stage you're satisfied with what you're producing will greatly improve any digital art later on. When in doubt, use a pencil first. This will also give you a greater understanding of how colours blend and how different materials work.Most of all, if there's a particular thing you like to draw often (animal, people etc) I would suggest finding references (photos) and for a while, draw exactly what you see. This is the best way to gain an understanding of anatomy. Much more accurate than trying to make your own while just looking at a ref. Draw the real thing first. Get used to the shapes and the way things align. THEN develop your style. This will give you a great understanding and make any characters or cartoon figures look both accurate and original because you haven't been dependant on imitating the style of someone else. Something I would have liked to know many years ago.Overall development takes time. You'll find that it'll be slow for a while and then you'll find something that works for you and the improvement will just explode. That was my experience anyway. The two most important things are, if you're passionate about art and drawing, never let yourself give up: if you're going through a rough patch or art block, just sketch ANYTHING that come to mind. And never, ever compare yourself to another artist. There will always be someone you're jealous of and who has better skills than you. Use this as inspiration and a desire to improve further. It's motivation to see better artists, not an excuse to give up.I hope you enjoyed my ramble