I don't think there are any spells, but i am not entirely sure on that subject. There are many ways to lucid dream. There are meditation, special herbs(non-toxic ones), You can also make dream pillow, it helps with lucid dreaming, prophetic dreams also. There are also certain types of gym stones to ues. One of the types of stones i like to use is Tigers Eye and or Amythest stone.
Now you can control dreams and create your own dream enviroment, which is mostly why its called lucid dreaming. Lucid dreams feel very real, from taste, to smell, touch, etc. But while you you lucid dream, the dreamer is is awhere of them dreaming.
I've always had trouble sometimes remembring which dreams where lucid and or astral traveling. But i am starting to get a little bit better at remembering which ones are which. But i still try to practice with them as much as i can.
I hope this helps you, if you kneed any help, just ask more questions.
Here is a simple way to get started on lucid dreaming.
This is what I would describe as an anchoring technique. Choose a simple behaviour, such as touching your nose, taking a deep breath, or, popularly, looking at the palms of your hands.
Practice this behaviour several times a day. The idea is that when you practice it, you connect it with the thought "am I dreaming?". Practice the thought!
Practice many times a day for as many days as it takes. Eventually, the behaviour will manifest in your dreaming, as behaviours do. As you have practiced the thought, that too will manifest. This time though, you will become aware that you are dreaming. You may be shocked into waking up the first time, but keep trying. When you can keep it together, you will be able to steer your dreaming at will. It is a handy technique if you suffer from nightmares, as you will be able to wake yourself up :)