The best advice I can give concerning kids at the scope is 'Make It Fun'.
Never talk in scientific terms (light-years, hydrogen etc) and be excited when you look at something. That makes them WANT to see it too.
Don't show them nebs then planets then Moon. They must be shown in order and with growing excitement. I start with Moon then planets. Then I will excitedly say "would you like to see something even further away?" Then show then 47Tuc or Omega Cent. Then say "how about something even further away!" This is where you can show them Orion neb (if in the sky). If that hasn't got them tingling by now, you can add, "Now how about something in another Galaxy!!!" and show them Tarantula!
If you want to keep them interested, you will have to put on a show. Get animated, make it exciting, growing in intensity. If you get excited, they will too.
I am usually exhausted after using this method coz I put heaps of growing excitement into it for them and my jaw aches from laughing
Also, kids like to ask questions like 'how far is that?' I won't let myself get bogged down in technical numbers that they don't grasp, so I say things like 'about a squillion gazillion kilometres away' and let then know I am joking, and I sometimes say silly things like "about a zillion zillion times around your oval". That one usually gets a 'Wow!'
You should enjoy it as much as them, so have fun with them. Works for me.
I avoid being serious with kids, coz 'serious' ain't fun, and fun creates interest.