OK, lets start a new thread here, Fly Tying tips.
Now make this a short discussion as it is not about tying a specific fly, ok.
Here would be a couple of examples to kick this thread off.
If you are going to wind a lead underbody for a number of flies. The most efficient way is to put the lead spool in a bobbin holder. You will waste far less and it is way easier to wind a neat lead underbody.
Thread control is one of the most important factors when tying. Tension of the thread spool held in the arms of the bobbin should be set so as when you wish for the thread to unwind from the spool it should do so easily and not require for you to have to use excessive pressure for it to do so.
If it does then adjust the bobbin arms.