After the Topic Sentence, you need to state your Point. This is something you want to argue or prove in the paragraph. 

Example

Here is a Thesis Statement regarding Santiago being a role model in the novella The Old Man and the Sea:

Through his humbleness, determination, and bravery, it is clear that Santiago is an ideal role model, which is important because Santiago motivates Manolin to strive for his dreams.  

Body Paragraph

First, throughout the novella, Santiago consistently shows a high degree of humbleness in his exchanges with people and the natural world. (Topic Sentence) During a conversation about fishing, Manolin says that Santiago is the best fisherman but Santiago shows his humility by disagreeing with Manolin’s opinion. (Point – about being humble with people) 

The Point here is that Santiago is humble when dealing with people, Manolin in particular, in the novella which underpins Santiago being an ideal role model for Manolin.