Why You're Always Tired (and how to fix it)

SUMMARY

1. Try obtain a consistent 7-8 hours sleep time per day.
2. Try match your schedule with your circadian rhythm, don't force yourself to wake up early or stay up late.
3. Use a melodic alarm.
4. Don't 'snooze' at all.
5. Physical exersice, exposure to bright natural light during daytime.
6. Hydrate yourself
7. Contain caffeine intake, preferably avoid caffeine intake 6 hours before bedtime.
8. Eat healthily. Avoid eating before bedtime.
9. Regular exercise, though avoid it before bedtime.
10. Napping before 3pm, preferably with length of a complete sleep cycle (~90m)
11. Warm shower before bedtime.
12. Avoid alcohol after evening.
13. Sleep in a dark, cool environment.
14. Put away gadgets from bed.
15. Don't lie awake, get up to do something and relax yourself.
16. Don't check time when you're awake midsleep.
17. Develop a healthy, consistent sleep schedule.
18. Value yourself, don't ignore your health or mental issue, seek professional help if you need to.

ADDITIONAL NOTES

There's a big biological difference between fatigue and sleepiness. Fatigue comes after activity (mental or physical – both create different type of fatigue). Sleepiness comes after inadequate sleep and is growing stronger during the day, due to rising adenosine. 

So, in a very simplified way, fatigue is a mechanical strain,  while sleepiness is mostly a chemical issue. That's why both states have a different solution. If you want to alleviate fatigue, you need to stop working and wait for your brain or muscles to recover. If you want to alleviate sleepiness, you need to get more or better sleep (there are 7+ different parameters that influence overall sleep quality). And after a few days or weeks, you'll get back to normal, because you will get rid of all of the excessive alertness-decreasing adenosine you accumulated over the past months or years.

Also. Both fatigue and sleepiness can be "masked" or enhanced by many other factors (diet, light, background noise, boredom ..). And both fatigue & sleepiness can be objective (brain & body function) or subjective (feeeling positive, motivated, vigorated). Studies show that, paradoxically, people who are objectively more sleepy (their cognitive functions are very low) usually feel more energetic than people who feel less awake (but their cognitive functions are fine). 

And as for the feelings of fatigue, they are mostly related to the perceived demands, rather than our objective strain or objective function. In other words, if you feel like the work demands are exceeding your capability to deal with them, you will feel tired, even if you're objectively OK.

Anyway, tiredness is not an easy topic. And anyone who feels tired needs to find out whether it's fatigue or sleepiness. Mostly it is a combination of both. But many people sleep fine and still feel tired. That's because sleep isn't a cure for fatigue. Or at least not for the mental fatigue. 

Cure for mental fatigue is mental recovery. Resting BEFORE sleep (so your brain is already relaxed, which improves the sleep quality) and DURING the day (taking breaks after 80–100 min of mental work, because that's the cognitive limit of our brain). That way your fatigue won't accumulate during the day nor between days. And then you will feel both awake AND rested. Not only in the mornings, but during the whole day. 

For more info about resting (with scientifically proven ways to increase efficiency of your recovery), check out these books: Rest (Alex Pang), The Art of Rest (Claudia Hammond) and An Oasis in Time (Marilyn Paul).