A thesis statement is a summary of the main claim made in the text. Good questions to ask include....
- Is it consise? (To the point, straightforward)
- Does bring the parts of the essay together (does it bridge the beginning, middle and end into a common theme?)
- Does it reflect the type of essay you are writing? (for example, an argumentative thesis for an argumentative essay)
- Does it accurately reflect the main point of the essay (could readers see the thesis alone and know exactly what the essay will be about, or is it too incoherent or thin on detail?)
Hope this helps!