Probably you should move a couple of eyelashes from the first sketch to the second one. And my biggest suggestion: from all characters, Milhouse probably is the only one whose nose is bigger than his upper lip.
Overall, the sketches look nice, keep practicing!
The first Lisa has the right lines, the propotions are just a bit mixed up. Eyes and nose are too big. Just small them down and magically the hair and overbite will look right. As Dagdamor said, the eyelashes must be 4, pretty short and simply curved.
Your "Lisa from memory" has a basic mistake that its easily solved. When you draw Lisa's head, you must remember that her (or any simpsons) eyes go all the way towards the face, and their cheecks start from beneath the eye only. the part of face between the eye and the side of her head you drew shouldnt be visible.
I like your penciling, though, and the first one especially. Keep it up!
A couple of rules of thumb you may find useful (I use them to check my drawing once they're finished - obviously, they all change for different poses):
- Lisa's upper lip extends horizontally almost as far as her outermost spike of hair, but farther than the edge of her eye.
- The line forming the bottom of the nose stops approximately vertically above where her lower lip starts. However, if it were continued horizontally, it would just clip the top of the ear.
- If the nose were to be made semi transparent, it should be approximately bisected lengthwise by the bottom line of the eye it is partially obscuring (obviously adjusting for the fact that this line is curved rather than straight).
- The vertical distance between the bottom of the eyes and the lower lip should be less than one eye diameter, unless she has her mouth wide open.
- The absolute distance between her ear and the edge of her eye nearest to it is approximately the same as the diameter of the ear itself.
- The circle which passes through the tips of the spike of her hair has a radius 1/2 to 1/4 an eye's diameter greater than the similar circle which passes through the points where adjacent spikes meet.
- As with all females, don't forget to include sugar and spice and all things nice. Though your pics show you have a good grasp of this already
- Sydney Brenner