Teach the young guys to be aggressive and have fun. Hitting should be fun not stressfull. Be relaxed and attack the baseball. Controlled aggression. Teach them some basic fundementals and let them learn how to hit in a relaxed and fun environment. How many times have you seen the dad yell at his 9 year old son while taking bp for jerking an outside pitch or lunging at a curve ball. The kid is so nervous that he is going to get yelled at that he isn't having any fun and he can't wait to get out of the box or{pressure cooker}. Kids enjoy doing the things that are fun to them and they love to hear positive feedback. Praise them all you can and then quietly tell them "Hey don't pull the outside pitch let it get deeper and then take it the other way". "But hey you did a great job up there good job". Thats what kids need to hear. There will be plenty of time down the road to jump them when they make the same mistakes over and over. If you don't make it a positive experience when they are young you wont have to worry about it later because they will find someting else that is positive for them.