The first of the Niyamas is saucha—which is translated cleanliness.
TKV Desikachar in the The Heart of Yoga: Developing a Personal Practice
defines this cleanliness as keeping our bodies and our surroundings clean and neat.The Hatha Yoga Pradipika specifies different types of cleansing techniques before a student begins practicing asana. The idea is to get rid of the things that are acting as impurities so that you can be better prepared for practice.
Is there anything in your world that simply needs to be cleaned? Is your desk cluttered? Are you behind on laundry? Do you simply need to spend some time manscaping?
Tackle an area where you need to practice cleanliness. For most of us, there is something we won't have to look hard to find.