Break it down into chunks.
a) come up with an (interesting if possible) question that you will answer. This might have already been given to you. State how vitally important this field is (always do this, no matter what the topic is!) Maybe something about how expensive top management is and how there has been increasing evaluations of the effects of these people to see if they give value for money?
b) define any business terms you will discuss - so define leadership and define management. Be careful here - leadership and management are quite different concepts. So compare and contrast them - don't simply substitute one for the other though-out the essay.
You need stuff like "Smith (2012) defines management as '.....'. Jones (2011) goes further by stating that it is also '....'. However, Wilson (2012) disagrees and defines management as '....'
c) Find out who has written on the subject. There are usually 3 or 4 key texts that you are expected to refer to. Hopefully you have a list from your college/uni.
d) from these texts find a minimum of 3 consequences (how many depends on the length required) Find out as much as you can about these consequences.
You could split it into effects on staff and the company if you'd like.
You want to find out which authors agree, which disagree and which think it happens only in some circumstances/sectors.
You also want to find some examples, either real life examples you can apply what you have found to (Steve Jobs is always good for leadership) and/or cases/questionnaires quoted in texts.
Your own research (in the company you work for?) would also be great here, but I suspect you don't have enough time! Make sure you evaluate each consequence - don't just agree with all of them - good and bad about each one.
e) Conclude with your own evaluation. Consider everything you have put above but do come down on a 'side'. Something like "although there are many disadvantages of poor leadership, the author feels that it is blah that has the most impact."
f) Finally, make some kind of recommendation of how your work can be used/improved on Maybe further evaluation is required or staff opinion sought.
Hope that helps.
I hope that helps!