I would say, if you insist on taking astral perception, to be sure you have either killing hands or a weapon focus, as well as the astral combat skill. Otherwise, any spirits will own you. The other option would be to drop the power altogether - yes, that means you won't be able to detect any patrolling spirits that might spot you, but you won't be putting a lot of build points into that area. You can only do so much before a character gets spread too thin to be effective.