I started practice out of Mastering Copperplate Calligraphy: A Step-by-Step Manual by Eleanor Winters. I ordered this book from an online source. I can't remember for certain, but I believe it was Barnes and Noble.
Anyway, within the introduction and first chapter I have already picked up some pointers to sharpen up my calligraphy skills. In some instances, I don't think I was holding the nib (I like the Brause 66EF flexible nib) with even pressure on both tips of the nib, which created fuzzy strokes. I also tend to apply a little too much pressure. I learned to avoid the the 'italic thrust' in the arches of some of the letters. I also, picked up a tip on forming lowercase 'H', 'K', and 'L' that will help me form them better. I will be using the Brause 66EF and walnut ink on marker paper. I am very excited. I am improving already.