Only a novice myself so take this with a pinch of salt, but here's what I do.
Hold whatever your tying in tightly in your left hand and use a pinch loop to position, add another loose thread wrap, then pull tight (worth practising to see how hard you can pull on the thread without breaking, it's surprising how hard you can pull even thin thread). Hold onto the material, or it will spin as you tighten. For something like zonker strips, keep hold of them as you move down the shank, it will twist, so just twist it back (if all else fails a dab of superglue helps

).
If you watch someone like David McPhail tying they are constantly adjusting the materials with their left hand, which is something I never used to do at all.
Hope some of that helps, Steve