When I'm spinning if I don't watch the fiber, sometimes when I don't the fiber is real thin - how do I stop this? Should I take out the thin part and re-do? How can I avoid this?
Practice, practice, practice. Consistency comes from attention & lots of practice. If your yarn gets thin, you can break off the fiber supply, let the yarn untwist just slightly, & join back on over the thin bit. The extra fiber laid down when you join-on will thicken the thin spot. But keep practicing at spinning a consistent size yarn. LT
At times you might need to shorten your draw to draft more fiber to make it consistent. This takes both practice and paying attention to what is going on with your hands and the fiber. Are you drafting with a short worsted draw like Judith McCuin or Margaret Stove teach? Or are you using a modified long draw? The type of draw you are using has a lot to do with the consistency of the draw. With either Judith's or Margaret's methods you will get very consistent thread. With a loose long draw method from top the fiber can quickly slip creating thin spots that you are trying to avoid. Practice with a short draw method to refine the consistency of the yarn.