Gather, sell. Keep an eye on the wards, check out which matter and which ore and which wood is selling for what amounts. Always keep an eye on +1 prices as well. I made an absolute mint (well, for me - at least two million gil overall) on Copper Ore +1's and Carbonized Matter at Horizon, and that's not a high level area. Haven't done that for a few weeks now but if you look around at the various prices I'm sure you'll figure it out.