Improving focus or concentration for better study skills:
Choose a comfortable place for studying. Check for back support and firm seat of the chair, comfortable table height, availability of books, plug points, lighting, ventilation and silence. Study in the same place every day.
Choose a convenient timing that you will adhere to. Do not change the timings unless it is an emergency.
Reduce clutter and keep your table neat and organized. Keep your cell phone in silent mode and put off light notifications or keep it in a drawer so that it does not distract you.
Make use of your support system. Inform your family that you wish to study at the specific hours and request them to not call you/pass on telephone calls etc.
The mind gets tuned to the timing and environment fast. Then you will find it easy to focus.