Note: If you are experiencing severe anxiety, then you need to look into a medical or psychological professional, such as a therapist. They can help far more than I. I am not a substitute for these professionals, far from it.
Meditation:Many ways to meditate. Visualization helps.
The theory is fairly simple. Your body and mind operate off stimulus and response: something happens and there's a reaction to what happened.
S ---> R
Resting Visualization: Does the stimulus have to be physical? Does it have to be "real" to have a response?
Consider the following. The Marines send a notice a woman's husband has died, KIA. She is devastated, understandably, of course. Turns out, they were mistaken. He's alive. The information was false, but her reaction was real and makes perfect sense. Point being, even false information stimuli can have real responses.
Consider an environment, yours, mine, anyone's. Horrible environment; horrible stimuli with horrible responses. Remember false stimuli and real responses (even if just placebo)? Imagine laying in bed trying to fall asleep there. Which is better to focus on what you can't control and worry, or imagine yourself in a nice place? Again, laying awake in bed trying to get to sleep.... If you worry, you lose sleep, are sleep deprived tomorrow, and anxious. If (laying in bed) you imagine yourself someplace nicer (meditate) you have a greater chance to sleep, be less anxious, and not sleepy tomorrow. Is it guaranteed? No. Does it cost anything? No. It's a simple idea (in theory), wanna think about horrible things or not, and which will help you fall asleep faster?
I know ... I know. Easier said than done. MUCH easier said than done sometimes. This is controlling your thoughts, and that's hard. Worth it if you ask me.
This is my understanding of meditation visualization. It creates a (false) mental stimuli, that may help feeling better emotionally ("happy place," etc). NOW, of course, it's important not to get lost in fantasy and realize it's not real (not losing touch with the real world). Is it perfect? No. It does provide some other stimuli to counter all the negative stuff a little bit. It has helped me sleep, if nothing else, through some terrible, terrible stuff. Of course, this assumes you have a safe place to sleep, etc, and I really hope everyone does.
Simply, what do you do when you are laying in bed trying to get to sleep? Worry or Imagine better.
Example: You've probably done RPGs, and/or read books with settings. Same idea, creating an imaginary place. Imagine another place and time, to the extent you can. It is possible to think of being on a gold veined marble beach terrace overlooking the sea, furnished with mahogany, attended by massage therapists, and visited by loving friends. That's just an example. I've used it in combination with progressive muscle relaxation to get to sleep.
Meditation as Organization:Consider mentally going over a "to do" list. This can help keep things organized and free up mental resources worrying about tasks.
Upon awakening, consider reciting some affirmations to reinforce some self esteem (
"The Meditations" by Marcus Aurelius helps (
I skip book one and go for book two) Also realize this was written by an ancient Roman Emperor, so it is from another place and time (it's going to be somewhat odd). You can of course do your own, something as simple as "I am a good person who does the best they can." It varies by person / situation, and this is another thing a therapist may help with.
These are, in my experience, some of the easier ways to do it in fairly safe environments (a bed, etc). If you are in a safe place with a few seconds to spare, it can be helpful to take 10 seconds to visualize a better place, while breathing out and in. Again, if you are in a safe place.... Annoyed at waiting in the grocery store checkout line, because the person in front of you is arguing with the cashier over coupons the cashier can't take because their invalid? I was last week and I quietly mentally went elsewhere while standing there, because there was no way around it. The fact of the matter was that I was going to be there for a couple minutes, it wasn't for work (no expectation of my producing results), it wasn't a dangerous place, and there was no better option. I know I wasn't really at a beach, but all other things equal, what better option did I have. Given I'm stuck there, I can either fume about this abusive customer, or do something else. Fuming won't help me and exhausts what few mental resources I have to spare. NOTE: always make sure you're in a safe place (Don't zone out while driving, or operating machinery, or any place that is not 100% safe). Only divert your attention when it is SAFE to do so.
On a personal note, I made a point to comfort the cashier somewhat after the difficult customer had left, saying I thought she handled that rather well and wished she didn't have to deal with that (within earshot of her manager).
I do hope that helps somewhat.
Disclosure: I have some real anxiety issues. I don't have all the answers. This helps me a little though. Seek a therapist if you have issues; they can help.