Methods are not the be-all end-all of shifting. Shifting is just becoming aware of yourself in another reality, and methods are just one way to do this. Some people can shift with many methods, some only use one, and some don't use any at all. I've created and tested a few methods, myself! These are all my own ideas as far as I know, but if they're not, let me know so I can give proper credit.
This method is loosely based on the Kingdom Keepers book series. You are allowed to move around to get comfortable. There is no specific position to be in. This method needs some visualization. I'd recommend affirming to yourself that your eyes will open automatically once you shift. If you want, meditating beforehand could help.
Listen to either a subliminal or calming 8D music, whichever you prefer. Plain old theta waves work too. (Optional-ish, recommended.)
Try to keep your mind awake. Think of something you know you have to do in your DR. This doesn't necessarily mean something you're excited about, but rather a responsibility you maintain there.
Take a few slow, deep breaths. Once your limbs are heavy and relaxed, continue to the next step.
Close your eyes and picture a light coming at you. Let it warm you, let it hold you. Let it swallow you whole, and know your DR is on the other side of this light.
Once you're surrounded by it completely, remember that thing you need to do. Imagine yourself waking up in your DR so you can do that thing.
When you know for sure what you'll be doing when you wake up, affirm that you're already beginning this process - opening your eyes to the area in which you'd start your day in your DR.
Imagine the light surrounding you growing more intense. Painless, but bright enough that you can practically feel your DR.
At this point, symptoms may be intense, but think of it as that falling sensation when you fall asleep. Even if you get no symptoms, you're getting closer and closer to your DR.
Affirm that you need to do that thing when you wake up. When your eyes open, you should be in your DR.
This method is shaped around how I used to shift as a kid, before I ever knew what I was doing. I call it the Lightyear method because the first reality I ever shifted to involved Buzz Lightyear in a sort of older-brother role. (I was seven at the time.) You are allowed to move around during this method, and changing positions at any point will not change its effectiveness. You don't need to visualize for this method.
This is mostly optional, but I'd suggest playing music or having a sound machine if you live with others, as this actively involves talking.
Find a comfortable position to start in. This should be no different than how you'd do this to go to sleep.
Pick one particular person from your DR. This person should be important to you, and you should have some sort of understanding of how you know them in your DR. (Friends, family, significant other, mentor, etc. but I'd recommend someone you'd feel safe to fall asleep around.)
Talk to them. I'm not kidding - just talk in the way that you would if you were really talking to them at around that time. You can talk about whatever you want, as long as you keep it centered around things that exist in your DR. (Events, memories, plans, hobbies, etc.) While you do this, think of their responses. You don't have to visualize anything if you don't want to, just think about it. Are they a good listener? Or do they interject with their own ideas?
Just keep talking about anything interesting you can think of. This activity, on its own, can connect you to your DR, and doing it while talking to someone from your DR only strengthens it. Talk as long as you want, but eventually, start to let the "conversation" wind down. Talk about mundane things until you fall asleep - you're already close enough to your DR after so long of knowing you're already there, and what you plan to do, so when you wake up, that's where you'll be.