NOTE: I STRONGLY recommend that you not do this with any ill intention as such spells VERY OFTEN BACKFIRE with very unpleasant and undesirable consequences. So make sure your heart is in the right place.
If I wanted to go into someone's dream state, you will have to have something of theirs, preferably a hair or a fingernail or something that came from their body. Then I would write your intention for going into their dream on a brown piece of paper (no lines). Use an odd number of reasons you need to go into their dream and what you hope to accomplish there: 1,3,5,7,9, etc.
Use a 5-6 foot length of string and tie it around your wrist and to the table you are doing your ritual on. This is to make it easy for you to FIND YOUR WAY BACK TO YOUR REALITY. YOU DO NOT WANT, UNDER ANY CIRCUMSTANCES, TO GET STUCK IN THEIR DREAM STATE.
Use some Dream Oil to anoint a candle that represents your purpose for going into their dream; white for helping them through a tricky path or through their bad dreams, pink or red for love, blue for seeking information, etc. After anointing your candle with the dream oil, sprinkle some Dream Spell Powder onto a plain white piece of paper and roll the candle in it until the outside of the candle is lightly covered.
Fasten a very small bowl to the center of a white plate. You can tape it or whatever, but you don't want it to tip over once you put the candle upright in it. Light your candle and place a few drops of wax into the center that small bowl, then fasten the candle to the bowl using that wax. Pour a few drops of Dream Oil into the small bowl and then drop the hair or fingernail into it.
Now meditate on the lit candle and upon your purpose. You will need to go into a trance-like state for this to work. Chanting can help, mumbling, murmuring, some mantra that comes from your deity that will help you get into your target's dream state. Then do your business.
NOTE: These items will soon be sold as a complete kit. Coming soon!