Avoid soap after seasoning. I use a copper scrubber (not stainless) on tough cleanup. Coarse salt and a little oil also make a nice scrub for carbonized food remains.
I used the oven method from a tip by America's Test Kitchen. I used flax seed oil, available from natural foods stores. You only need a small amount, so buy the smallest bottle you can find . Keep it cold in the fridge. The flax oil creates a lacquer-like smooth seasoning layer. I used about 8 baked on very thin layers. Search for flax oil and seasoning on the net for cast iron.
All new seasonings are fragile. Avoid acidic foods and soap. Re-season as needed. Over time, the seasoning will strengthen with regular use and good care.
I recently purchased a 16" southern China style wok from e-woks. To make a long story short, It is exactly what I had searched two years for. The wok is sturdy and quite deep. It is truly a hand made item, not just finished by hand. I use an outdoor burner for this, and every wok I use. A stove just can't put out the heat needed. To season, I used flax seed oil. I applied about 8 thin coats and baked each one at a time in a 450 degree oven. The coats were allowed to bake 30-45 minutes followed by a cooling period. After it was cool, it was washed with a copper scrubber. The resulting seasoning coat looks like black lacquer and gave a great base to start cooking with. Prior to seasoning, I scrubbed the wok with a stainless scrubber and hot soapy water, and then with Chinese garlic chives to remove the metallic taste from a new wok.
All in all, this wok is absolutely beautiful and a fine example of the dying art of a hand-made wok. These woks are not cheap and the freight is not cheap, but if you want an authentic artisan made wok, these are it.