Starting out is the hardest part. It takes years to refine your art style. Some things to consider:
1. Find a piece of artwork you like, and try and copy it. This will teach you the basic motions and things to consider. If it doesn't look as good, why? What is missing? This will help you learn.
2. You can learn art by looking as much as can doing. I spent a couple of years just browsing artwork on the internet. This was important for me because it helped me understand what sort of style I wanted to go for in terms of colour, composition, and shading.
3. Don't be afraid to trace. Try and trace freehand though. This way it'll take you many attempts to get it right. Like in the first point, if it doesn't look right, why not? It will teach you importance of details and how tiny differences can greatly affect artwork.
4. Read up on complimentary colours. Usually you can just see if a colour combination is not working out, but it helps to not guess.
5. People will tell you to stay motivated and not give up, but in reality "art block" is a real symptom. If you aren't feeling up to it, give it a few days or a week and try again.
Some of these points are controversial for some, but really the quickest way to learn is to get right in to what you want to do. That is copying artwork. Obviously you don't then promote that artwork as yours, but the importance is the learning, not the result, until you feel confident producing original art.