For the Plebe-to-Be . . .
Think "we" not "I." As in, "How can I help US be better" vs. "How can I be better than them."
No one cares how great you were in h.s. or that you had 3 noms or that you were admitted to all 5 SAs or that you had an LOA or that you were valedictorian and team captain and . . . Everyone around you was just as great.
Do your best at every evolution. Recognize that there's a lot that's new for most (sailing, shooting, marching, etc.). You'll be great at some things and not so great at others. Ditto for your classmates. It's ok to be not great at everything. You earn the respect of your peers and detailers if you give 100%, even if that 100% isn't all that terrific.
Get used to being hot, sweaty, sticky. For the women -- no blowdrying, no makeup (you won't want to wear it other than Sunday mornings). It does get better Ac Year.
Write your parents -- even if just a postcard. It means a lot to them.
Realize the old adage, "Look to your left; look to your right; one of you won't be here in four years" is no longer true. If you want to stay, chances are >95% that you'll get through.
And read the sticky by Memphis at the top of this forum.
Parents . . . I've written this almost every year . . . WRITE your kid. My father wrote me every single day (and I do mean every single day) that I was at USNA. Mostly it was just "stuff" -- what he did that day, what my mother did, what my dog did, what the neighbors did. My mother sent me newspaper clippings (in the days when we had newspapers

). I can't begin to tell you how great it was to have a letter at every mail call -- everyone was so jealous (in a good way). I suppose as a WWII Marine, my dad understood how important it was to get letters from home. It seems hard -- just do it. Set aside 10 minutes each day -- your plebe will never forget it.