Not to sound like an asshole, but there is nothing to redo here. It's too generic to use as a basis for a character, and too simple to use it as a pose for a character. Just keep practicing, you'll get better.
paper and pencil dont matter, draw with and on whatever you want (i use a4 size computer paper and a mechanical pencil). go to www.fineart.sk for some figure and anatomy drawing. study the loomis books like theyre your god
You can find A4 paper anywhere.. practice with different types of pencil until you find something you like. I sketch with a ballpoint pen sometimes, so you can try that too.
Just like Yutani and Vertrucio said, just draw stuff you see. Practice drawing headphones, cups, other people, family members etc. Try different techniques when drawing shadows and stuff like that. Im no pro, but I can tell you that drawing at least a sketch a day will improve your skill.
But if you really want to improve your drawing... focus on drawing real life things before you start drawing your ideas.
Fire up a thread in the daily sketchbook section and add at least a sketch a day, then after a few weeks see if you notice a difference.
Hmmm... looks like I have a lot of time on my hands.. id better get back to sketching