OM said pretty much exactly what I was thinking, especially:
  • Take your time and explore.
  • Make it an enjoyable experience for them (get them hooked).
Also remember that every kid is different. Some kids are naturally adventurous and want to explore. Some may need a little more time and patience. Be sure and listen to them, and I bet they will come to love the outdoors and hiking. I can't stress enough how important it is to imprint positive first memories on them if you want them to keep enjoying it later in life.
The journey is more important than the destination.