I follow the Northern Path of Shamanism and Magic, but there are elements in any magical ritual that will determine if it will be powerful and effective.
1. It must have a powerful beginning and ending. A ritual that begins on a weak note loses it's significance. Just as when you meet someone for the first time, the "first" impression is very important. If your beginning does not attract the attention from the participants, higher ones, be they gods, beings etc., with it's strength and sense of purpose very little will be accomplished.
This is the reason why so many rituals begin with drums, bells, whistles or trumpets. You get a strong beginning by doing "something" to get people's attention. By the same turn, a weak ending leaves everyone participating feeling unfulfilled and incomplete. You achieve a strong ending getting everyone's attention again and letting them know clearly that the ritual is over.
2. The ritual must have strong sensory input. You will only be impressed and influenced by a ritual that you are watching to the degree that it is interesting and beautiful. If it has music and scents it will have greater effect. Add to the that the other senses of touch and taste, the effect will be even more powerful.
3. It must have a familiar and predictable form. If you participate in a ritual and do not know what to do next or what to expect, you will be confused and anxious. This in turn will cause you to be distracted from the ritual causing you to have less of an influence and less of an impression. But if there is enough about it that is familiar, you will feel more comfortable and more affected by the ritual.
4. The meaning of every part of the ritual must be understood by the participants. Any part of the ritual that is not understood by all involved causes the ritual to loose it's effectiveness. Sure the person directing the ritual knows what is going on. But it is the strength of all involved in the ceremony that gives the ritual strength. So in shamanic rituals you will usually find everything explained before and during the ritual.
5. The ritual must be special. If a ritual does not look or feel any different from any other occasion it will loose it's effectiveness. The major reason why so many of our modern rituals seem empty is that so many of our leaders no longer treat those rituals as special. This is most evident in our holiday rituals. Hallows, or Halloween has been reduced to a costume party. Yule, or for many people perceived as Christmas, has become a shopping frenzy. New Years day is just a hangover and a football game. So make your ritual stand out and be noticed.
Brightest of Blessings on Your Ritual,