This is only constructive criticism, I'm not trying to hurt feelings! :)
For the body:
I can see your trying to copy a minecraft character avatar, to the arms should be connected to the neck.
Where the left arm folds, there should be a cut, like a real elbow would have. From here, it looks like it is broken. (If that's the correct word.)
If your trying to copy a minecraft avatar, you should add a bit more meat to the body, to get that minecraft avatar sort of feel.
Add some extra details to your clothing. Maybe some rags, some tears in the shirt, etc.
For the background:
Add a bit more things in the background. Maybe some trees, the sun, and a home, unless you want that type of look.
Try and make the background contrast the colors of your character.
If you can, add your YouTube name to it. It will add a personal type of feel.
Overall, it is okay. Work can be added to it. Take your time! This is the first thing someone will see about your YouTube channel! :)
Good luck with your channel, and be sure to make some great content!
- PAL143