@loveliw
You could try those videos on youtube with like "Asian mom helps you study" - i thought it wouldn't work for me but when it's late at night and i'm procrastinating i throw it on and end up fearing for my life lmao.
Erm also timers do help so you can be mindful of how much time you're spending on doing things and how long your breaks are- it helps you not waste too much time as well.
Before you sit down to start studying, make sure you've got all your homework/study organised, you grab a bottle of water or beverage (preferably a healthy one but you do you- i personally have a bottle of water and a cup of tea), put some snacks on your desk, make sure it's well lit and clean and if during the day and weather permits- well ventilated. Wear comfortable clothing- but not 'lazy/home clothes' as that can make you feel 'informal' so actually get dressed/ changed, wash your face, do your hair and then try and get started. If you throw yourself into something with no plan you'll get a little stuck.
When motivation fails rely on discipline, because motivation fluctuates, allow yourself a proper timetable or way of doing things, like a 'ritual' when you're motivated and when you lose focus, your body should become accustom to the structure you have set for yourself.
BUT REMEMBER- to always take breaks and understand when you're body may be too tired and take a 20 min nap or get out of your study space and chill for a little bit before getting back into work
Hope this helps