When it comes to feathers, I am a BIG advocate of doodling and drawing feathers until I can do it without thinking about it.
That said, I have some sort of mental block, I can ONLY draw and quilt feathers going from the bottom up. So if my feather has a spine, I start the spine at the top of my plume, make one line of the spine and then make my feather loops from the bottom up. When I reach the top, I zip down the second line of my spine from top to bottom then do the other half of my feather loops, again from bottom to top. I have tried and tried to do them from the top to the bottom and I mess up every single time. Others out there may have the same issue so if you are having trouble with feathers try only doing them from bottom to top. That said I can do a feather in ANY direction I just have to do my loops of the feather working from my perceived bottom to my perceived top. Hard to explain, easy to show.