I keep the phone as far as possible. I keep a glass of water near by. I pee before starting. And for longer periods I keep some snack also nearby.
For concentration, I usually listen to podcasts or Storytimes on YouTube because it helps me stay focused for an extend period of time.
First… for me it depends on what I’m studying and from what source. If it’s school studying, I would do the following:
Read assignment and take notes on it. Real notes on paper. Not just highlighting passages. Or jotting things in margins. The act of distilling the assignment and putting it in writing help me remember it.
Attend the lecture. Take written notes again.
Get home and combine my book notes with my lecture notes. Keep all three.
Start all homework assignments when assigned. Do not wait til last minute. Go to professor during office hours with questions.
If it isa language class or any other where it would work, make flash cards and study often.
Do optional assignments or readings.
I have modified the same sort of things for learning things for work where possible.
Yes… it takes time. Mostly it takes a desire to really know whatever it is.
In terms of focusing on work… deadlines focus me if the project doesn’t. I really hate missing them. If it’s something I love I get so involved I forget to eat etc.
If you have something that you have to learn that you’re really not interested in. The only help I’ve found is looking at why I’m studying whatever it is and focusing on that if it’s something I want.
In terms of absorption, teaching someone else is the best method for retaining information, but beyond that everybody is different. There are online quizzes you can do to find out which kind of learner you are, but some ideas to get you started are summarising chapters into a fixed number of sentences, reading the title/introduction and spending a little time trying to predict what may come up in the following passage, and turning important info into a song.
Each individual is different so try lots of things, persevere, and see which one works for you. Then tell your friends!