Nighttime was created for Torah study. Therefore be more careful with your night learning. Someone who wastes his time at night gets more severely punished than wasting his time during the day. (ShA1 – MB1)
Someone who wants to merit Kesser Torah must make sure not to waste any of his nights with sleep, food and drink, idle chatter etc…. This applies even to the short summer nights. Learn at least a little bit before going to sleep. (MB1)
Some poskim are machmir not to read p'sukim at night. There is no prohibition, just that it is better to read those at daytime similar to Moshe’s lessons from Hashem: p'sukim during the day and mishna at night. (ShaH1)
Say you have a set daily quota of Torah study. If one day you were too busy to get it done, do not go to sleep. You are obligated to stay awake and finish your quota. (ShA2 – MB4)
It is best to stipulate at the outset that this daily quota (or any good deed) should be b’li nedder, lest one time it happens that you won’t be able to fulfil it. (MB5) LAWS OF MAARIV