If this is the first tutorial you make, I would keep it simple. I create tutorials and believe me, what seems a simple tutorial gets complicated very easily. Make sure the subject you choose for your tutorial, you know it inside out. Creating a tutorial and still learning the subject will not go well together.
Whatever tutorial you create, make sure you design your outline first. Then workout that outlines and start scripting your tutorial. When the outline itself is finished, that will give you a very good idea about the tutorial and what is necessary.
I look forward to knowing your decision about which subject you will make your tutorial. Choose something you like to do, not what we like you to do. Something you can put your heart and soul in! Remember, it is YOUR baby!
Keep up the good work!