I often noticed Naruto characters look OOC (not like themselves) and I'm often told I draw them very in-character. So I thought I'd make a little "tutorial" here...
Read on for more info on each character. These three are the most susceptible to "character assassination". Sure, everyone has their own style of drawing, but changing the character's overall impression is not a matter of style anymore. For example, I like to draw characters a little more "emphasized" which means, I make Sakura's forehead really large or Kakashi's chin more distinct. BUT Sakura will always have her cat-eyes and Kakashi will always have his droopy eyes no matter what style I draw them in, even if I imitated Arina Tanemura or Natsuki Takaya. If the shape of the eyes or the stance are characteristics needed to make that character who he is, they cannot change. So please don't use Orlando Bloom for reference when drawing a realistic Kakashi....

Also keep in mind I exaggerated it alot in the BAD drawings. But I did see such Kakashis, I swear. That's so not Kakashi...

KAKASHI GOOD
Kakashi is 26, but he looks much older. He's got those tired droopy eyes with little wrinkles around them. He's already seen everything and is hardly impressed by anything. His eyes are "tired of having seen it all". He's confident and sometimes a little rude (NOT vulgar!), he likes to laugh and be sarcastic. Also, he's very seedy and relaxed. A big mouth fits best for these characteristics.
And although he's not Gai, he's still a man, so don't be shy and please do give him eyebrows. A thin black line is not an eyebrow. He's thin as you can see when you pay attention to how his cheek area is often shaded. His face is a bit sunken-in. Don't give him a girly or hamster face. He's a 100% male. Edges, edges, edges, not curves! Some male characters can be "womanized" to a certain degree, but not Kakashi. Also, since he's a man, don't make his hair a shampoo commercial.
As for his build... he's rather thin, enough muscles to look like a fighter, but not a Marvel superhero! Also, he's rather pale.

KAKASHI BAD
Alert, awake, big, up-tilted or otherwise bright eyes are not for him. Kakashi simply isn't the type to have big, curious, cute or otherwise explicably big eyes. He's not visibly alert, he's not a daydreamer and he doesn't hop through fields of flowers. As for the tiny nose, WTF? He's a grown man, give him at least 6cm of a straight nose. Draw the bridge of the nose if possible or at least indicate it at the base between the eyebrows. The small mouth doesn't work. Small mouths characterize shy people and daddy's good girl/boy. Kakashi is rather trashy though. He'd listen to Nirvana, not Backstreet Boys. As for his hair, as stated above, don't turn it into a L'Oreal commercial.
And since he's a man, don't turn his body into that of Yuki Soma (Fruits Basket). But please don't turn him into Hulk Hogan either. He mostly fights with brains, speed and small moves, not brute force. And remember he's always hospitalized, so he does lack stamina. Hulk Hogan does have stamina or at least he looks like he does.

NARUTO GOOD
Naruto's a cheeky, bold, wild and (over)confident teenager. And a prankster. He'll have smart eyes, uptilted and open, looking for the next opportunity to rock. He's happy and cheerful and tries not to cry too much. So there's no reason for wet droopy eyes. Droopy wet eyes are for fragile crybabies, Ritsukas and Tsuzukis. As for the mouth, we all know Naruto's got a big mouth. Maybe not as wide as Iggy Pop, but big enough to shout and boast. Naruto is not a puppy who comes crying for love. Naruto's a fighter who gets things in his own way and he's confident about it. His hair stands up wild and spiky, as rebellious as its owner. It reaches out for higher grounds, just like Naruto always does.

NARUTO BAD
Those eyes cry twice a day and they beg you for love, affection, abuse and what-not. Naruto isn't like that. This is another person. That small mouth never says "no" or "Let me handle it". This mouth hardly ever opens unless it's spitting out Hinata-lines. Also, although it usually isn't a problem, his drooping hair is a problem in this case. If at least his eyes were tilted upwards and his overall impression was confident, but in this case, it emphasizes his pathetic overall impression. This kid is a beaten puppy-dog left for dead.

TEMARI GOOD
Everything about Temari radiates confidence and sexiness. Note: a skinny flat spaghetti with big eyes is not sexy. Unless you're a child molester? She has flesh. She has curves to give you a nosebleed. Giver her a body. In French, you call well-built women "Bien roulée" - "well-rolled".
Also, Temari is confident, smart, aggressive and dominant. She's a leader type. Slanted eyes with a somewhat strict/commanding expression are best for her. Her eyes should tilt up. Never droop or oversize them. Temari may be only 15, but she's more of a woman than a little girl.
VERY important: yes, female legs tend to turn inward (X-legs). But in Temari's case, try to keep it down. She's a ruffian and the oldest sibling of 2 boys. She's lived and grown in mostly male company, so this should have influenced her. So her posture is NOT that of a Magical Bishoujo/Sailormoon/Miaka Yuki/Cardcaptor Sakura. Her overall impression is far from fragile or shy.

TEMARI BAD
This skinny spaghetti isn't only malnourished, her legs may give any minute. She won't be able to handle the shock of seeing a bird kill a bug. She'd collapse and cry her droopy eyes even droopier. She's so shy and helpless you just have to smack her up.