how is plagiarism preventable?

cite sources accurately.
create your own sources rather than using research.
ask for an author's permission.
write a paragraph summary of where you found your information.

Change some of the wording and work cite it.

Explanation:

I do this all the time and never get accused of plagiarism.

explanation:

it's important for any number of settings.   but then i'm a retired teacher and my view may be biased.

it certainly will not weigh as a minus when applying to a college, while poor grades always work against you.

other factors are important like what you do to improve the community.