Although it may seem counter-intuitive, writing your introduction first may be more difficult to accomplish than starting with the meat of your paper. Starting by writing the main points (focusing on supporting your thesis) allows you to slightly change and manipulate your ideas and commentary.
The introduction is, in many respects, the conclusion written in reverse: start by generally introducing the larger topic, then orient the reader in the area you’ve focused on, and finally, supply the thesis statement. Avoid repeating exact phrases that you already used in the conclusion.
If you choose a topic, begin researching, and realize that it isn’t the right decision for you for some reason, don’t fret! Although it requires a bit more time, you have the ability to change your topic even after you begin researching others.
If you are struggling to come up with a topic that feels “just right,” ask your professor or coworkers/classmates for advice. They will likely have great ideas that, even if they aren’t options for you to choose, can inspire you with new ideas. Asking a professor for help may seem frightening, but if they are worth anything as a professor, they want you to be successful with your work, and will do what they can to make that happen.