One strategy I remember was that if you got the right build against some foes you were literally invincible and could have low enough damage that you wouldn't destroy the enemy.
So you could use that to level up your crew to all locations, which was a pretty big gain, especially early on and before / without clone bay (with a clone bay your dupes are expendable and lose skill, so getting them to level 2 is less valuable).
My Shrike minmaxing strategy typically involves o2 depletion to whack enemy ships out and get maximum rewards. But it does frequently require a lot of waiting.
So you could use that to level up your crew to all locations, which was a pretty big gain, especially early on and before / without clone bay (with a clone bay your dupes are expendable and lose skill, so getting them to level 2 is less valuable).