Think and discuss with your parents and hopefully school counselor about what you can afford and what you are looking for in a college. What kinds of career paths might you want to go down. Also think about things like location, size of school, climate, culture etc. Start getting a list of possible schools or at least an idea.
Next think about what you're looking for from running. Do you want to be a top-7 member of a good team, do you want to be the top runner, would you be happy even not making top 7 if you could race in B races and track.
Once you figure that out, look into your list above, their teams success and recent recruiting classes. Do they normally get people as fast as you, faster, slower. Try to find out their scholarship situations, coaching styles if possible.
Then start emailing coaches. Put your best PR time and some academic credential at the top of the email or subject line. If you want to go to a good academic school, having good GPA or test scores is a helpful selling point to the coach. The rest of the email should briefly sell yourself and say you're interested, ask for more info about the program.
Don't worry if you don't hear back from all of them -- they're focused on recruiting current seniors right now. Email your favorites back after cross if you had a good result to brag about, and email them all during late track season or after track with an update about your new PRs (hopefully).