I will be teaching a short course in pranayama in March 2017, which will introduce you to the anatomy of respiration, the preparatory practices, and a few of the traditional breathing techniques. The course is based on the teachings of pranayama master O.P. Tiwari, director of the Kaivalyadham Yoga Institute in India, with significant input from Richard Freeman.
Some breathing techniques can be elusive; and it can take weeks or months of consistent practice to achieve proficiency. Consistency, patience, and maturity are therefore helpful when approaching the study of pranayama.