1: NW, BH's, Daily quests, and LGTM. Plus there are some ONE-TIME only quests which reward good amounts of ST too (see the Goshiki sidequest chain)
2: Get your R8 done first.
3: Get 12 runs of LGTM done, get your cape, and upgrade it with supply tokens and SoW at a NW forge.
4: Do everything you can, excluding GV
IF YOU CAN HELP IT.
5: Save up and merchant.
6: Use your r8 gear, it'd be much better than the 130/140 gears out there atm (use Dragon if you have it tho, and ONLY IF you have a full set.) It costs literally nothing to transfer refines/gems here.