My Errors

Here are my mistakes:
1. My thesis statements are weak and irrelevant to my whole essay. Since my thesis statement fails to clearly state the purpose of my essay, my whole essay doesn't make sense to the reader. I never know what to put in my thesis statement, so I pretend to do so, but never accomplish in succeeding a good thesis. I hope to improve in writing my thesis statement by first getting an idea/or writing my whole essay, and then my thesis statement.
2. My second mistake would be understanding and clearly writing about the topic. I am confident about what I am writing when I am writing about, but when I get my graded paper back, reality hits me, and I did not understand the topic; therefore, my essay is weak. I honestly don't know how to improve in this. When I read something I understand it in my own way, but apperantly not the way it should be. I do know one way is asking others what they captured from the reading, but that's all I think that can help me.
3. Tying it all together is another big thing. My paper lacks consistency through out it. I just write and write without looking if the writing is connected, which makes my paper sloppy. I also never know how to end my paper and tie it back to the beginning. The conclusion is another thing that I have a hard time doing. A way I can improve in this is actually spending more time on it than I do now.