There is no more straightforward way to say it: to recover from hard training sessions (and trigger those much hard-earned training adaptations) you need to sleep. However, you don't only need to target a certain amount of hours of sleep, you need to sleep well during that time. The quality of your sleep is equally — if not more important — than the quantity of your sleep.

I don't want to sound like a broken record and keep repeating that you need to sleep and that you need to sleep well. This time let's look at some science and dig out some more info.

I love to sleep and I've read several papers (and a book) on the subject, including the exhaustive "Recovery and Performance in Sport: Consensus Statement" (1) (which gives an extensive description of the different recovery strategies you can adopt to recover from sport-related stress and fatigue) -- but for our intent here, let's look more closely at "Sleep, Recovery, and Athletic Performance: A Brief Review and Recommendations." (2)

I rounded up here the most essential suggestions and guidelines to make sure your sleep is re-balancing the stress and fatigue levels from your daily routine and training sessions.

1) A right balance between stress (training, racing, and life routine) and recovery is essential to achieve a high level of performance.

2) The pressure you get from everyday life and training is both physical and psychological.

3) Monitor your stress and fatigue to avoid under-recovery, overtraining, injuries, or illnesses.

4) Sleep has been identified as one of the crucial recovery tools that contribute to optimal athletic performance. But to get there, you have to improve your 'sleep hygiene.'

5) You should get 7-9 hours of sleep per night to get enough physiological and psychological recovery (80-90% of this time should be during the night). This can be very different from person to person, but sleep the amount that it makes you feel wakeful and alert throughout the following day. (3)

6) Poor sleep quality, particularly when you train hard (or higher volumes), has been identified as a marker of under-recovery and an early sign of overreaching.

7) If you have problems sleeping during the night (fatigue can also affect your ability to fall asleep, particularly if you train late and you perform your high-intensity sessions in the evening), consider napping. Even a 30-minute post-lunch nap (I always try to get it in, but I know my set-up is quite different from most of the people).

8) If you sleep more, your performances will improve.

9) Avoid behaviors that affect the quality of your sleep. In other words, protect your sleep! Including, but not limiting to:

Try to maintain the same sleep patterns (going to bed and waking up at the same times).

Wash your face before going to bed. This will help cool down your body temperature (as well as sleeping in a room at around 18°).
Make sure your room is dark and quiet.
If you can't fall asleep, get out of the bed, change room and do something else (like reading with low light)
Keep a silent alarm on your bedside table and keep your phones outside of the room.
Limit the consumption of caffeine to the morning (I stop drinking coffees after noon and I drink 2-3 coffees max per day).
Alcohol consumption will negatively affect your sleep quality.
Limit the time you spend staring at your phones and screens before bed (and set them up on a lighter light)

And of course, implement the above recommendations one step at the time. Do not try to change your patterns all in one, but try to sleep more, sleep better, and perform better!

References

(2) Bird, Stephen P. Ph.D., published on the Strength and Conditioning Journal: October 2013 - Volume 35 - Issue 5 - p 43-47, doi: 10.1519/SSC.0b013e3182a62e2f

(3) Calder A. Recovery strategies for sports performance, in USOC Olympic Coach E-Magazine 8–11, 2003