Here are some things to keep in mind and that will help you improve your art, especially if you're a beginner.
1. Good art takes time
Don't expect to finish a good piece of art in less than an hour. If you want your art to look good you also have to be willing to invest time in it. Good drawings can take weeks to finish! So have patience and take your time for your art.
"I should never copy, copying is the same as stealing. Everything I draw has to come from my mind only." - NO. NO. NO! Quite the opposite! If you can you should always use references! Take whatever inspires you (photos, drawings, games, anime, creature designs, etc.) take whatever colors you like! Copying is NOT a crime or even a bad thing! Just make sure you always have multiple references ready - the more the better! DON'T just copy ONE image. Mix them together, add your own fantasy and make something new and unique! And if you're a beginner it is okay to even copy whole images for practicing purposes! In that case though you should not upload your practice drawings unless you have permission to do so from the original creator. This also counts for photos!
Try to always make more than one sketch before you start defining the drawing. They can be really rough sketches that take less than a minute to make - little thumbnails with different perspectives, moods, formats, angles, poses, colors. They will help you decide on a composition that works well!
Before you start drawing you should collect inspiration and references. Look through dA, Pinterest, Artstation, Google, whatever and find things that are related to what you want to draw. They will help you with #2 and #3.
5. Think about what you're doing
Try to find out why you're doing things the way you're doing them and don't just do them. Find out how people you admire do those things. Why did you chose this brush for painting? Is there a brush setting that might work better? Why did you chose this color? What could improve the quality of this drawing you're making? Don't stop asking questions while drawing!
6. Custom brushes
Yes these are great! I'm using them, too, and I'm using them a lot. But why do they look so good when some people use them and look crappy when you're using them?
Because they are not meant to be the final thing! Personally I use custom brushes in sketches and paint over them in the process to integrate them into the picture and into my style.
Example of not very good use of custom brushes: Wolf Sun
Better use of them: Take My Home II
(Yes, those were both made by me and they both use 90% custom brushes.)
Looking at them helps. We all have things to learn! If you don't know where to look, try these out:The Ctrl Paint Library
- A great collection of short videos that will help you with a wide range of topics.How to Draw Backgrounds with Character
- Among the best things I've found on dA to this day.My Favourites
- Some tutorials I found helpful.
Or simply this: #tutorial