I also recommend videos by Boo. Pay for them.
Find a clinic. Go, pay attention, ask questions.
Make sure the kids know how to sprint properly. It makes all of the difference for hurdles and jumps.
Film your own kids, show them the video and ask them what they see. Feedback from your own kids is necessary.
Advice for jumps is to keep kids on a short approach early. Practice and meets. They stay in control of there bodies, less likely to foul, lets them focus on specific things at a time.
Find some videos on youtube of the best athletes. Olympic and WC videos are great because you see the race, and usually 2 or 3 angles in slow motion. You can really have good teaching sessions and you can learn yourself.
Email, call or find in person 2 or 3 of the best coaches in your district/county/state. Ask them a question or two or one thing that they look for.