I would humbly recommend Mining & Skinning, creating 2 alt accounts with 18 bank characters run to the capital city of your choice (Orgrimmar or Ironforge come to mind as best) and save all ore, all stone, all cloth, and all skins collected from 1-60.
At that point, pick the trade skill you actually want and then max it in one shot.
In terms of making money solely, as per your post, it would be a combo of Mining & Herbalism (if you can toggle both like clockwork as needed) and simply watching the market for what to sell. Wool, Silver ore, Thorium & Dense stone are the usual candidates. For herbs it's going to be that sweet sweet dreamfoil and black lotus.