The very first thing you should do when wanting to shift, is research. This is a good start, but also venture to different platforms. In my reading lists I have a collection of shifting guides I've found on Wattpad that will be helpful and informational. I also highly recommend blxueshifters on tik tok (she posts a lot of different methods, as well as other information about shifting, clones, subliminals, affirmations, etc.)
this is where i've learned most of what i know about different methods.
I also joined an Amino group called Reality Shifting, you are able to ask questions and join chat rooms which makes it much easier to communicate with other people interested in shifting.
They have chat rooms for almost everyone (Hogwarts, various anime worlds, etc) and if you don't find one you like you can make one yourself!
Blxueshifters also has a discord server which is linked in her tik tok bio where you can ask questions, interact with people who have shifted, and more!
These are all resources that have helped me, and searching shiftedrealities on tik tok will bring up much more information, however you cannot trust everything you read, especially on tik tok.
Many people claim shifting is unsafe or you could get trapped or killed in your desired reality, but it is your desired reality, you will be able to get back, however you should ALWAYS take precautions. When you script (even if you choose not to, at least write down these basic precautions) make sure to script yourself a safe word/action to leave your desired reality. For example:
"If I clap three times and say chicken pot pie I will return to my current reality"
You should also include that you cannot be killed or badly injured in your desired reality, and that you will not retain any physical or mental trauma from your desired reality.
With these precautions in mind, know that what you feel in your desired reality is real. If you suffer through a traumatic event in your DR, you can try to script that you won't be traumatized, but it cannot be guaranteed. You can script that you will not miss the people from your DR when you return to your CR, but they are real relationships you have made, and even if you script that you won't feel anything, you likely will.
That being said, there are no physical dangers of shifting, only mental ones. Avoid shifting into a reality where you will suffer trauma (a war, supernatural characters, etc.) unless you know exactly what you are getting yourself into and script your safety.
You should also avoid traumatizing anyone else in your DR, realize that they are real people. When you are in your DR they are not just characters, or your imagination, they are real people and you should spare them any pain you may want to put them through.