Rugby Lock Question?

I've been a lock for 4 years at my college and we've recently lost all but 5-6 Vets on the team with 30 or so new guys coming in to fill spots (Yeah it was a pretty bad loss of guys last season) Anyways, Im haveing difficulty locking with these new bunch of guys, even after I explain to them what to do and show them things, I still find my head extremely and dangerously lose doing a scrum. Any tips as to how I could possibly better my situation? If not, what are some lock tips you'd like to share, as Im always willing to hear what people have to say. Thanks again