I have the miniature clocks, and one big clock. I love teaching with those! Each child has their own clock to manipulate. I start off going through a few simple questions (show 9:00, show 9:15, show 9:25, etc...). Then I'll do a few easy elapsed times (if it's 9:00 now, what time will it be in 30 minutes?), and they show it on their clock. Before I check it, I'll show how to find it on my big clock for any kids that struggled finding the answer. After many examples like that, we move into harder ones (You're going to your friend's house at 10:00 and your mom said you could stay 3 hours, what time do you come home?). I think it really helps them to be able to move the hands on the clock.
If you don't have the little clocks, let the kids make them with small paper plates and brads.