I personally believe it depend on the person regarding the herbs. Personally I experimented with a lot of different teas and incence in order to find what suited me.
I would reccomend chamomile, mugwortor or valeriana for tea, citrus, ditany crete and rosemary for incence.
I would may benefit from calcite and amethyst. Moreover some people believe calsite could be benefitial.
However I would suggest that if you are a begginer you shouldn't experiment with incense, herbs or stones of any kind. You should first practice your meditation and visualisation without any help.
I suggest that due to:
The fact that you may actually need them to achieve any level of meditation.
The fact it may actually block you from experiencing any level of meditation if you are a begginer and you have yet to experience meditation or any kind of out of body experience.
In case you are a bigginner I would reccomend you to practice your meditation and visualisation before you attempt astral projection.
I agree with Fox's post and recommend you follow her advice if you're starting out, but when you've accomplished a fair degree of success with meditation, a thin, translucent piece of carnelian is said to work well if you hold it in front of your eyes and visualise your astral body travelling out from your eyes and projecting on the other side of the crystal. I haven't used this myself but have read about it, hopefully it helps :)
I already do have a very good understanding of meditation, as I meditate for at least 30 minutes every day. Though typically most of this is what I call active meditation. I meditate and focus while I'm doing something like H.E.M.A.. Though I do believe it is practiced by Shaolin Monks as well.