Preparation for any test or an interview needs some practices without which you can't prepare that efficiently, if not now, you might regret later for not following these practices.
Set a goal: If you are preparing for something, your willpower should be so much and you should strive for it every moment and that is the first and foremost thing
Sticky Notes: Make a habit of using the sticky notes effectively.
you can get them from online stores.
Whiteboard: Especially if you are preparing for some interviews, get a whiteboard for yourself, assume that there are a few audiences in front of you and explain them loudly with your voice. this practice helps you figure out the mistakes you are doing in your regular practice.
If you can't afford to buy a new whiteboard, get one white chart and a transparent sheet of the same size, paste the chart with the transparent sheet on it on the wall with the help of a transparent tape and it looks like this.(it was my DIY whiteboard)
Calendar: Try to add your events and schedules to your calendar( it can be your calendar app on your mobile or google calendar or physical calendar)
Schedules: Make some fixed schedules and set some time regularly for practice, my suggestion is to start with less time like 30 minutes or 45 minutes and you can scale it up later.
To-do list: Understand what are the things you need to do and make a to-do list wisely, In sticky notes, write everything but on a to-do list, generalize the tasks.
Reminders: we generally have a habit of forgetting our activities or plans. so make use of reminders to keep reminding them.
I have personally observed the difference in seriousness and productivity using these methods, hope it helps you too.
PS: all the images used here are for representational purpose only