Aside from doing all the free quests, see if there are any interludes for the lower star characters (may have to level them up and get some bond points, I think, though). Also, when there is maintenance, hope they have to delay it, as they tend to give "apologems" quite regularly. Only a limited supply of them right now, so hard to say aside from plugging away at those and keeping the daily login streak going.
Or spend $$, but from my experience (starting from January '16), they tend to give good amounts of free ones overall.
Edited by Xellos, 11 July 2017 - 10:04 PM.