Singing
Kirtan should be performed in the mood of glorifying the Lordships, singing with sincere devotion for the pleasure of Sri Krsna and His devotees.
When singing in a group, one or two persons should lead and other devotees should follow.
The instruments that can be used for kirtan are harmonium,mridanga, kartals,etc
Use simple melody and preferably the appropriate melody (raga) for the time of day.
Kirtan Competition:
If our peers are leading very beautifully and are getting a lot of praise for the same(more than us) we should feel very happy that they were able to please the Lordships.
If we feel bad about this, then maybe our singing was to get praise from other devotees and not for the pleasure of the Lordships. For if it was for the pleasure of the Lordships we would have been very happy with our peers singing so wonderfully.
Dancing:
"Regarding your question about the dancing, the dancing should be doneenthusiastically by raising the hands like Panca-tattva. You can alsodance enthusiastically by raising hands. All of Lord Caitanya's followers used to dance with raised hands. If someone dances with ecstasy, that is all right, but it is better to dance with raised hands." (SP Letter to Kirtanananda 11/10/74?)