I posted this awhile back, and I think it still holds up:
My advice to Freshmen:
1. Don't go all "High School Harry" and talk about races you won, times you ran, etc. They don't mean $hit any more. Just wipe the slate clean and start over. Your team mates will learn how fast you are in due time.
2. Do NOT keep your HS bf/gf. DO NOT DO THIS!!
3. Don't assume your team mates are "runners". Sure they are getting scholarship money, but there are a lot of them going through the motions and they are very negative. Avoid their negativity at all costs!
4. Buy into the training. Resist the urge to only do what you did in HS or lean on your HS coach.
5. School is going to be hard. If you just walked through HS (like I did) this will be a rude lesson. School is the #1 priority, you will not be a pro runner, but you will be a pro something else post graduation.
6. Go to parties and have some fun, meet more people than XC team mates. If all you do is run and study you're missing out. Doesn't mean you need to be a party animal, but you do need to experience some "normal" college life between seasons.
7. Run like hell. This is your chance to run as fast as you probably ever will run. You have a coach, support, time, and training /rehab resources. You also get to race against some runners that will go on to be great. See where you match up.
One of the great things about our sport is that if you go to a big meet you can race a national champion, even if you go to Podunk U.
8. On a similar point, you are finally racing your peers. This isn't HS where you know that out of 300 kids at a XC meet you are only really racing 10 of them. Everyone is good. Don't let that freak you out, embrace it.