The thesis statement is the conclusion of the paper.

A good thesis statement is precise, succinct, and informative.

It is not simply a statement of the general topic, interest or plan.  Nor is it a springboard to jump into other topics.

Consider the following compare and contrast thesis statements:

1.  Rule utilitarianism and Kantian ethics share certain similarities and differences.
2.  Both rule utilitarianism and Kantian ethics emphasize rules, but they are also different.
3.  Confucian and Aristotelian ethics are more dissimilar than suggested by Chang Wejen in his paper “Confucian Theories of Norms and Human Rights.”
4.  Aristotle’s notion of harmonious functioning for the relationship between a ruler and his subject is fundamentally similar to Confucius’ notion of reciprocity.

1 is clearly the worst, as it is not at all informative.  2 is a little better, but still lacking in specificity.  3 is pretty good, but not quite as good as 4, which is the best of this lot because it has the greatest level of specificity.

But the best compare and contrast theses go even a step further by showing how what appears to be a difference is really, at a deeper level of analysis, a similarity (or vice-versa).  For example:

5  While both Kantian ethics and Aristotelian ethics seem to emphasize individual conduct, the Kantian system is more applicable to matters of social policy.

6.  Despite the fundamental difference in how Kant and Aristotle ground morality, it is possible to derive a right to autonomy from both their ethical systems.  [In the introduction, one would then go on to elaborate on what autonomy is and what it means to have a right to that autonomy].

Here's an example of what I mean when I say that you can try to defend a particular way of combining elements of both into a coherent hybrid theory.  The philosopher David Cuminsky recently proposed to incorporate  Kant's theory of value intoa  consequentalist framework. I would summarize his thesis as follows:

7.  While the consequentalist is essentially correct that we should be trying to maximize the good, the Kantian idea of grounding value in autonomy or the good will provides the best account of the good.