Work the market. Find an item that no one else is selling and exploit it for a while. But like Misakie said botanist and miner are hard mainly due to bots selling on the market. Once you start making a little gill you gain a little control over the market as you can buy out under cut prices then re-list them at a higher value. There are also videos online with some suggestions but they only work for a short time as everyone starts catching on to the trick. Just take your time and don't settle for less than you want to get on an item, and if the market value is too low for your taste just keep the item and craft it out. I'd be more specific but I don't want to loose what little advantage I have.