Problem with those guides is, everybody follows them.

Sure, gather a bit, sell the excess, and you'll get gil.
If you pick a crafter that can make that into something somebody wants to buy... (and here's the hard part) you make a bit more.
Money does not roll in quickly at the start, unless you find something somebody missed.

I will say though, instead, just do the MSQ a while. There's an easy half million gil between level 1 and 60 in MSQ rewards. Part of why bots do that over and over.