Noob Naru's Noobish Get Rich Soloing Guide for Noobs
Step 1: find out what items, especially cards, are for sale for lots at pront merch shops
Step 2: find out what mobs drop that stuff
Step 3: Choose from these mobs one you can farm and level off of (use RMS to consider things like their elemental weakness, what map they're on and how many there are on that map, what equip you'll need, their hp-to-exp ratio, etc.)
Step 4: Kill lots and LOTS of the mob you chose.
Step 5: ?????
Step 6: Set up your own merchant shop to sell the loot you got.
Step 7: PROFIT!!!!
~Naru's Extra Tip~
Do not, and I repeat
do NOT go to the popular mobs that everyone farms. Hillwinds may be easy to kill, but they're INCREDIBLY boring and unoriginal. Also, you'll be competing with everyone else to mob them and chances of idiotic HW drama is high. Find a mob with a really useful card that no one else thinks to level off of. This way you'll get a chance for a super valuable item along with the NPCable drops and exp.
Or just do parties instead of soloing