What are Jem's strengths and weaknesses in the novel To Kill a Mockingbird? Also, if upi know his appearance (such as what he wears, what he...

Though readers follow Scout, the narrator in To
Kill A Mockingbird, as she matures and begins to understand the important
lessons her father teaches her, Jem is the character who matures the most over the
course of the novel. 

Part 1 of To Kill A
Mockingbird focuses mainly on the children's obsession with Boo Radley. 
Though Jem is older than Scout and Dill, he encourages, and even organizes, attempts to
lure Boo out of his house or communicate with him in some way or another.  Atticus
continually reminds the children to leave Boo alone, but the mystery of the Radley house
is too tempting for them to forget.  As the eldest of the children, Jem should be the
one to heed Atticus's orders to leave Boo alone, so his failure to do so might be seen
as a weakness.  However, readers must remember that though Jem is older than Scout and
Dill, he is still a child. 

I think the best example of
Jem's weakness--if we can call it that--is the impulsivity he displays at the end of
Part 1.  After Mrs. Dubose insults Atticus, Jem chops down all of her flowers in a fit
of rage.  Again, though Atticus consistently teaches his children not to retaliate when
people speak badly of him, we must remember that Jem is only a child and that children
are often impulsive.  Also, Jem learns a valuable lesson in courage by spending time
with Mrs. Dubose as part of his punishment. 

Part 2 of the
novel marks a period of immense growth for Jem.  In Chapters 12-14, readers watch Jem
mature; Scout notes that Jem is moody, inconsistent, and acts as if he is superior to
her and Dill--behaviors that annoy Scout very much.  Also during this time, however, Jem
begins to exhibit a better understanding of the world around him.  As the focus of the
novel shifts to the trial of Tom Robinson, Jem sees--and is disgusted by--the injustice
that exists in the town of Maycomb.  In the incident outside the jail in Chapter 15, Jem
openly defies Atticus when Atticus orders him to leave--a decision which shows that Jem
understands the danger of the situation and knows that it will only escalate if he takes
Scout and Dill home. It takes courage for Jem to defy his father, but he does so because
he is developing a mind and will of his own, along with the maturity to make responsible
decisions.  Thus, Jem's moral development, compassion, and  sensitivity in Part 2 can be
seen as his greatest strengths.

For a physical description
of Jem, see Chapter 15; Scout, while watching Jem defy Atticus, observes that while Jem
possesses his mother's physical features (she describes them), "mutual defiance" makes
Jem and Atticus seem to look alike.