The thesis statement in an essay introduces the topic, telling the reader what the essay will be about. In a personal essay it also it lets the reader know the writer's position on the topic. For example, a personal essay on the topic of school uniforms would reveal whether or not the writer is in favor of students wearing uniforms to school.
The thesis statement of a personal essay gives the reader a glimpse into the argument the writer will make in the essay, capturing their interest enough to read the rest. For example, the thesis statement on the school uniforms topic should reveal the reasons why the writer is or is not in favor of students wearing uniforms to school.
Tone in a personal essay is the expression of how the writer feels about his opinion on the topic. A good personal essay thesis statement will set the tone of the essay. The writer's word choice and sentence structure should communicate how strongly he feels about his opinion. For example the reader should know from reading the thesis statement how strongly the writer feels about whether or not students should wear uniforms to school.
The writer should include in her thesis statement a brief summary of the argument that will be made in the rest of the essay. The paragraphs that follow should each fit into the container created by the thesis statement. For example, if the thesis statement indicates the writer feels strongly that students should wear uniforms to school because doing so cuts down on competition among students and puts all students on an even level, she should write specifically about those two topics. She should not include a paragraph about how clothing choice reflects a student's personality and therefore uniforms stifle a student's personal expression as this does not support the argument made in the thesis statement.