Of the gatherers, I'd recommend miner.. they have more items that crafters need. For retainer ventures, quick ventures are an RNG crapshoot (could get vendor trash chubs, or multi million selling kingly whiskers) or shards are a low cost/low selling but consistent gil making method. The good quick venture items do need max level/decent gear I believe, so for the short term, maybe leveling with 18 hour ventures and sending them out for shards for gil would be best.

If you are actively leveling a battle class, you can do leves and sell the gear. NQ heavensward gear on my server will sell for 5k-30k, so I pulled in a small amount of profit just from hitting my weekly challenge log bonus.