#1:make up your mind on the shadows, there are two different shadows in the shot...
#2 make it more detailed.
#3: use a sharper pencil.
#4: your cord looks like plain shit, work on that more.
#5: shadows should be smooth, dont have pencil marks visible... BLEND, take some TP and some paper then mask it.
#6: put the picture in the middle of the shot, center of attention.
#7: dont put a red border on, its too distracting.
#8: use shapes at first, then put in the details... so first draw the rectangle then smooth out the corners to get the effect you were going for.
and finally #9: on the connecter on the cord, thats pretty decent actually but you made it darker then everything else, so it looks too much different... and different is bad
just look for specific areas of colors that are different, dont look for lines seperating areas, if u draw all the different colors and shadows as different shapes you'll get the flow better