I'm really struggling to teach my sons this. We've made clocks, we look at the clocks in our house, nothing seems to work. Well, my oldest has kind of grasped that the small hand points at the hour, but he doesn't get the concept that before the 12 is TO, after the 12 is PAST. Any suggestions, how did you teach your kids ths? Thanks.
Good luck! Let me know if you figure it out. My daughter is almost 13 and STILL struggles with this. She has learned somewhat the past the hour, but doesnt always get the TO the hour and still struggles with reading a regular clock. Hard where so many ar digital as she 'll search out the digitals.My son did not get time until fractions in 3rd grade, Some how he aced fractions and I showed him a circle with two lines across to make 1/4 s. That is how he got half past or half after and 1/4 till etc. The thing he still cannot get is like 1& 1/2 hours from now. He finally learned to count the minutes but I could never get him to count by 5's or 15's If it is 2:40 he may have to count the whole 40 minutes. Maybe next year. Just keep at it...I want my children to understand the fundamental basics behind it. Same reason I insist they learn how to write a letter before learning to email and SMS. Besides all of my wall clocks have proper clock faces 
My 9yo doesn't fully understand the before/after thing. I've retrained myself to always say it's twelve fifteen, rather than it's quarter after twelve. I know they try teaching them both ways in school, but he often gets before and after mixed up in lots of different contexts, as well as still having difficulty with right and left, yesterday and tomorrow.
My issue is with digital clocks. It only tells what time it is RIGHT NOW! Planning and internalizing the passage of time is our challenge.
I have put decorative but working analog clocks in every room of the house. We have large ones near each of the dining areas. Yes, even in the bathrooms.
One item I was interested in, though haven't tried yet, was recommended by a local Executive Function coach. The timer shows physically the time passing as the red area shrinks.
When my son was learning, I covered all the digital clocks (vcr, microwave,etc.) with tape so that he'd have to go to the analog clock in the house. Also, whenever he asked if he could do something, I'd say, "Well, I guess you can in.. (insert whatever number of minutes works for you).. minutes. What time will it be then?" and he'd have to figure it out on the clock before he'd get the final okay.
I also agree that the language we use to denote before and after the hour can be confusing for kids. We started using "before the hour of" and "after the hour of" until he really knew his stuff. Then we went to " 'til" and "after."