There are many ways to go about getting recruited for college sports. My suggestions are broad so that they can cover a variety of sports. But recruitment varies per sport.

Email coaches directly: I would suggest that you target schools that fit the student both academically and athletically and reach out to the coach directly. Make your email message unique and add in a fun fact about the school to show your interest. Attach your recruitment video to the email as well.
Create a recruitment video: Design a video that highlights your position in the sport. Do not make your video too flashy but just show highlights of your play.
Fill out online recruitment forms on college’s athletic website: Complete the recruitment questionnaire to express interest in the college and team.
Attend showcases, camps at select colleges and play travel/club sport (if applicable). This will give you exposure to college coaches.
Remember when speaking to coaches to be polite and formal. Good luck.