think someone in the thread has hit on best way to skill it up:  get soaring leap & use that constantly.  I get skillups going downhill crossing the continents.

I used to try to keep it capped per level for the first few but that started to get harder and take longer, now I basically just run up and jump up whatever happens to be on my path.  If there's a rock, I run up it and jump off.  If there's a hill, run up and jump off.  I get a skillup occasionally and it doesn't take much time out from other things.  I'm up to about Safe Fall 189 that way.

I can fall ridiculous distances and take at most 100-300 damage if any.  I get the impression it is possible to "critical miss" though, I rode the Leth Nurae water slide to the pool at the top of the goddess statue, arced out into space from the top of that and died on the rocks far side of the lake at the base of the statue.  But that was back around skill 120 or so.

But yeah, if you just get in the habit of running up any incline and jumping off anything that you happen upon, you will raise it over time without a lot of trouble.  It doesn't really seem to matter how high either as long as you get airborne, it's just skillups are less frequent.  (can't confirm this.)