maybe ooshmaster mentioned that already (don't wanna read his 'article' now =) but this extremly lacks of contrast and has this pillow shading feel on it..
For a first try this isn't bad. I can see that you have a great grasp of the mouse as a tool and the outline it self is well done. But ofter that is where you need some more practice. The main thing is the shading. I see pillow shading on the leaves. This is one of the worst thinks you can have in pixel art, but don't worry, almost everyone as had it in their work when they were just learning. Pillow shading is when there is no real light source, or the light source is between the subject and the viewer. This is an easy mistake to make if you aren't paying attention becuase you just start shading the outer edges towards the middle without realizing. There are some great tutorials in the links page that will help with that. On the branch and pot, you have established light sources, but they are in opposite directions. The light on the branch seems to be coming from the left, yet the light on the pot is coming from the right, which makes no sense. In doing something like this, it helps to pick a spot where your light is coming from and mark it on your piece. This helps you stay consistent with the lighting and you can erase it after you're done. The other thing is the colors, which isn't too big a deal right now for you, because your just starting, but keep in mind that when a transition begins to look to smooth, it doesn't look pixelated anymore, which is the whole point of pixel art, so you know you have too many colors. When you are working on your peice, try to recylce colors as often as you can, and if you see two colors that resemble each other too closely, get rid of one shade. This will make your art look much better.
Last but not least, do some real-life drawing. You can bet that all the really good artists on this site started with a pencil and paper first. Take a drawing class. This way you will learn all you need to know about light sources, cast shadow as opposed to form shadow, color theory, and so on. Then you will know half of what you need to know in order to make good pixel art. I hope this helps. Good luck, and I hope to see more of your work in the future!
