economy is difficult to understand at the beginning; true
once you understood it its asy however
but basically its like: exchange always goes up when sales are and goes down when no sales are
cheap sales like prophetic cards let it go up extra high (because the small prices per compass are affordable for almost everyone by exchange)
upgrading takes out gold of the cycle of economy while activities that generate gold put gold in
the longer the game runs the higher the exchange rate goes
once a new levelpatch comes, activities that generate gold give MORE GOLD, which leads to an adjustment regarding the exchangerate (means you can get BC easier)
in one sentence economy is like: you buy things cheap and sell them expensive
as a newcomer gearing is of very questionable usage, i personally do not recommend it
just upgrade runes, they stay; gear will be softreset (new better gear comes with patch 6.0!)
we have a thread about farming here as well which sums up pretty much every activity that is useful for gaining gold
once you have enough gold to buy things get them cheap and try to sell them more expensive
this way you get gold "for nothing" (but handing things over)
the gold you get you use to buy more things for resale
as for crafting, you can offer making leveling gear, some players tend to give out relatively large sums of gold for getting purple gear for their level (especially level 29 purple items are wanted)
same with highest possible craftable gear (those who want to not gear but be better than ferris blue repgear willl buy it)
last way is speculation; if you buy BC while its 1:275 then sell your BC while 1:305 and it goes down to 1:280 or something again, you buy BC again and you have also got currency "for nothing"