If your sleeping 7 plus hours a night and still feeling knackered it's worth talking to a doctor and having some tests done, there's loads of reasons for feeling tired all the time.
In terms of improving sleep having a consistent sleep and wake time is super important and having a wind down routine is helpful.
If you struggle to get to sleep a good technique is to get up after 15-20 minutes (not timing but when it feels like you've been trying to sleep that long) and do something with a low thinking requirement like reading a book or watching bad TV.
It depends. I usually sleep pretty well, but I have a bizarre tendency towards lucid dreams, sleep paralysis, false awakenings, and even "involuntary astral projection" where I have the sensation of leaving my body. I figured out that CBD and cannabis help stop this, so lately I've been free of most sleep disturbances.
I unfortunately drink too much and smoke so rem sleep doesn't happen a lot. Falling asleep is never really an issue but it's just never good sleep. That turns into drinking half a pot of coffee to get going in the morning. Then repeat, I'm always tired
I struggle keeping to a sleep schedule, to the point that I suspect I have a non-24 hour sleep wake disorder.
On some days, I may be asleep during the day, and yet on some days, I operate on a "normal" sleep cycle, only for it to be broken in a few days. Trying to do "normal person" things requires me to plan things ahead, usually through extending my wakefulness such that I'd be asleep the night before I need to be on a "normal person schedule."
However, when I do fall asleep, I'm dead to the world for a while, sometimes exceeding twelve hours. Upon waking up, even if I've only managed to sleep for a couple of hours, I find it hard to sleep for until more than eighteen hours later.