It might be interesting to examine the way the title is reflected in Obi's conflicts throughout this work. Why, exactly, is he uneasy? What causes his discomfort?

It is also often helpful to structure your thesis in a way that organizes your paper. I often advise students to build three main points into their thesis and to have each of those main points become a body paragraph.

Using this structure, a thesis for No Longer at Ease might look something like this:

The unease Obi experiences in the novel is created by economic hardship, divided loyalties, and unforeseen tragedies.

From the beginning, Obi experiences economic hardship. He is in debt because of his education and can't manage to get ahead. Early on, he holds tightly to his values and refuses to accept bribes to award scholarships. Yet the tension of debt impacts his relationship with Clara, making it more difficult for him to marry an osu.

Obi also struggles with a sense of divided loyalty between people, particularly Clara and his mother. His mother places Obi in a particularly impossible position when she vows to kill herself if he marries Obi. On the other hand, he is engaged to Clara, who he discovers is pregnant. The inner turmoil of this conflict adds to Obi's unease.

Unforeseen tragedies also create a growing sense of unease. Obi falls in love with an osu, whose position is unacceptable to his family. Clara becomes pregnant, and neither she nor Obi want a baby, because the conflict with his mother creates a barrier in their relationship. Clara suffers complications following an abortion and can't receive visitors because she is too ill. When Obi returns to work, he learns that his mother has died; his mind spirals into growing turmoil, and he opts not to go home for her funeral. Obi faces numerous unforeseen tragedies that increase his inner instability.

In your conclusion, you could examine how these various points of unease contribute to a character who finds himself on trial for accepting bribes, proving that he has greatly changed from the man who refused bribes early in the book and before his various conflicts.