I'm currently not enrolled in University, but enjoy studying and researching as a hobby, at least until I am able to go back to Uni.
What I do is read through a chapter in a quick manner and briefly and quickly outline it from memory. Write down any questions that may have popped up.
Then I through and try to critically re-read it. I'll go paragraph by paragraph or section by section, and then write a brief summary of each paragraph or section. Once I'm done with that, I organize it a bit, touch it up, think through what I've learned, ask more questions, try to answer any remaining questions using the available material, and review.
If you want peace and quiet, there are many places you could go. Try your university's library, try going to a park, if you're able - lock yourself in your room and make it a bit cool (cool air generally helps people focus a bit better), go to a local library, just be on the lookout for possible quiet places. Be creative.
If you don't mind noise, or actually focus better with noise that isn't something like voices or lyrical music, maybe try listening to instrumental music. I find that when I read, listening to electronic, dubstep, instrumental metal, or classical music can help me drown out distractions, isn't distracting due to a lack of lyrics, and can help me focus overall.
If you're in a class where you want to retain the information and not simply pass, there is a term some people use - "over studying." Basically it is review to the max. It is really only necessary if you want to retain the information for a longer period of time, or know that you'll be using the information as a building block for future information.
Also, a good way to remember things is to associate them with things already in your life experience and knowledge.
Another good way to remember things is to compare terms. This is a very basic example, but say you have two terms -
Mathematics and History.
How are they different? Mathematics uses numbers, formulas, equations, and is generally abstract information and data. History is based on events in the past, things that were at one point very tangible, and because of their tangible nature, can even be imagined more vividly than abstract information.
How are they alike?
History is full of dates which is simply an arrangement of numbers. Mathematics uses numbers.
Etc, etc. Comparing and contrasting terms, or ideas can help with remembering them and more fully comprehending them.
Another method would be to try and explain what you learned to someone else. This is generally only available if someone is willing to listen to the material, however

Also, some studies have been done that people generally can only maintain focus on an objective for about 25-30 minutes. This is, of course, a generalization, but if you find that this is the case with you, then set a timer (if you have a smart phone or a watch with an alarm, this could be easy) for the time you think works best, engage in the focused activity, and when the alarm goes off, give yourself a 5-10 minute break. Go stretch, walk, drink something, eat a snack, text someone, etc.
Oh, and one more thing. If you find that social media, or even websites like Youtube are distracting for you during your study/homework time, I recommend checking out a website called "ColdTurkey." You can block other websites in increments of 10 minutes, all the way up to a week. I find it very helpful when I realize I'm spending too much time on a single website or am being too distracted.
Blessings!
~ Jacob