What should be the posture during chanting?
Best is to sit and chant japa. For those who find it difficult to sit and chant, walking and chanting is also acceptable. One has to be careful of not falling asleep, so try not to be too comfortable. Particularly in the early morning hours, you may find it hard to keep from nodding off. For that reason, some devotees prefer to go for 'japa walks'. You can go outside and chant as you circumambulate the temple or go for walks in the neighborhood. When 'japa walking', try not to become too distracted with visual experiences. Ideally, you should simply be hearing the Holy Name and thinking of Krsna in some way, shape or form when you're chanting His Holy Name. In many temples, the men circumambulate the front portion of the temple, by the altar, while the women circumambulate the rear half of the temple during the morning japa period. Many devotees circumabulate around tulasi and chant their japa.