I've had DP for about 3 months now, and I learned some stuff that really helps me manage DP/just random stuff I've learned and I want to share it, so I can try to help someone.
1) Sleep. The more you sleep, the better you'll feel. I try to sleep from between 8 hrs to 10 hrs. If I don't, I'll feel like I'm going to drop down dead at any moment, because I get so tired. But sleep the enough amount for you, since everyone is different.
Also try to sleep at proper hours, and wake up at proper hours.
2) Take your attention out of DP. This is the hard part. It took me about a couple of weeks to actually learn how to do this, since it was so overwhelming. I'd end up having a break down, and I would start crying and simply freaking out. It takes a couple of weeks to learn, but you'll end up learning it. Just distract yourself with something else. For me, it was a game and Youtube. Also, since school started I had to pay a lot of attention to it as well, because it's a really important year.
It works, and I forgot I even had DP. It was still there, but you kinda don't notice it.
3) You are not crazy. As I've said many, many times crazy people don't know they are crazy. They don't realize something is wrong with them. You do. Maybe right now it seems like you are, but you aren't.
4) Exercise. It normally really helps me. Keeps my attention out of DP and I start to focus on what I'm doing. Plus, it helps me sleep really well at night, and of course, also helps me get in shape.
5) Start thinking positively. It may seem impossible right now to be positive, but do you know how lucky you actually are? You don't have terminal cancer, you don't live in a place where a constant war is happening (I assume). I assume that you are lucky enough to be able to go to school, and to have food in your plate, a warm bed to sleep in and a roof over your head. And if you are reading this you also have a computer/phone and wi-fi connection.
You are really lucky to have just DP. As I've seen somebody else say: "Everyone goes trough dark periods in life, everyone goes trough hard stuff. This is what we were chosen to go trough. Imagine the people who were chosen to have terminal cancer. Do you want to be them? Probably not."
6) If you have had any trauma, or if you maybe feel a lot of guilt, go fix that problem. If DP comes because it's a mechanism to help us deal with stress, then it's probably trying to protect us from something, a problem. A trauma, perhaps. Try to fix anything that causes stress in your life.
7) Quit googling your symptoms. It's extremely awful to do so. You'll probably freak out, because we all know that all problems we have turn into something bad like "Oh you have a belly ache? Guess what, you have cancer!". Don't google stuff. Mostly, some stuff aren't true and it will make you freak out for no reason.
8 ) Go outside. Do something with your life! When you are sitting in your computer, googling your symptoms for hours, and hours on end your brain will just get tired and your DP will get worse. It's not healthy for anyone to stay all day at home.
9) You'll start feeling your DP go away after a while. At least for me. I'm starting to feel better, and better everyday. Yes, I still have DP 24/7, but I still feel like I'm getting better. After a few months, you'll start feeling your DP progress slowly. It's a slow process. Remember that your brain is a powerful machine, and it needs time to recover.
10) Do something you love. It'll help you get distracted from DP, it's really helpful.
11) Your sleep may feel really weird right now, but you will get better. Trust me. For about a month I couldn't sleep right. Dreams felt like real life, and real life seemed like a dream. You'll start to sleep better after a couple of weeks, don't worry!
12) It cannot kill you. DP is only a feeling. It cannot kill you, and it won't kill you.
13) Get yourself some good old therapy. Personally, I don't have the money for therapy right now. If you do though, that is probably a good idea.
That's all for now! I hope it really helps someone overcome some of the issues that come with DP Sorry for any mistakes or something. Sometimes I make really weird/bad mistakes when I'm writing (that's just how my brain is sometimes), so excuse me for that.
Anyways, have a good day!