For undergraduate students who are required to submit a thesis, the first hurdle is to get the thesis statement approved by the adviser. The thesis statement is basically composed of your subject and your opinion/bias/thought/contention/argument/ about that subject. Subjective, it is, but it should also be based on the available resources. That's why before you create a thesis statement, first you have to do your homework. Google or do a library research (prefer library research) of your TOPIC. The following questions should be considered during pre-research even before a thesis statement is made:
What interests you?
This initial question drives you to the books and other resources, so that when you, for example, google an information YOUR GOOGLING will be specific enough. Example: on the topic of PETS, google: "They say my cat can cause hives" - you look for information on this one, since you love your cat and would probably like to disprove this. Note that you may find out other things about cats which can lead you to your specific subject.
List down three OTHER researchable topics ON THE SUBJECT:
Example: Cats and hives, Cats and training cats, Domesticating wild cats etc. Note that your topic cannot be too wide or too narrow. These two are the reasons why your adviser will reject your topic. Then consider how a topic affects you
Accordingly, go for the topic that will keep you reading about it.
How will you use this information later on?
Save the resources you find as you may come back to them later on. If you are doing a library research, note down in a 3 X 5 index card, the resource information of the book or webpage. Copy all information needed, and as you would write it in the Recommended Readings or References Section. For how to do this, google the style set by your school - usually, this is either MLA or APA. Don't forget to copy exact information because when you quote or paraphrase from this material, you need to cite the source, otherwise, if you forget, you will be plagiarizing.
Based on your pre-reading FINALIZE YOUR SUBJECT. Subjects cannot be too general as in "Cats." Don't just say, "I'd like to write about Cats". The next question is "What about it?" To answer this, try to go to a specific aspect of your chosen topic, that is, "Cats Eat Rats". This then, becomes your subject. Only then can you finalize WHAT YOU CAN SAY ABOUT YOUR SUBJECT. Example, if you chose "Cats Eat Rats," you can go scientific and say that cats eating rats doesn't make cats uneatable - that is, people can eat cats and the taboo is baseless. You can go to the benefits of keeping many cats as pets, especially in farms so the rats would be kept out of the field.
You can brainstorm and list down as many as you can think of regarding "Cats Eat Rats". Nailing down this statement will be your THESIS STATEMENT and this point has got to be ARGUED. This means you have to PROVE your opinion/bias/thought/contention/argument about your subject by offering enough data to SUPPORT IT.
Once you have nailed your THESIS STATEMENT, have it approved. Consider all the suggestions of your adviser. Your adviser isn't there to make you suffer; she is there to help you THINK CRITICALLY about a specific subject. This CRITICAL THINKING skill is valuable at all times.
Maybe you think that a thesis is simply to meet the requirement for graduation. But what you learn from even the formulation of a thesis statement will help you in making wise choices.