The oldest penmanship society in the United States was founded in 1949. It is a leader in calligraphic education and the non-profit association is dedicated to helping artists of all levels improve their skills. Get the latest news on their conventions, sign up for their newsletter, take one of their many free online lessons and find a number of other great resources on their site.
Periodically use your favorite nib to create a sample. Compare samples over time to help determine how your nib is wearing and whether or not it might be time to replace it.