|Buy Low, Sell Higher|
I tend not to 'sell high' as my server has a few fairly high profile goldmakers who usually beat me to the best markets. I'm very casual in my gold making, especially now with all the distractions provided by Mists of Pandaria! Selling high is also a subjective thing - what is a high price to you may be an okay price for others or it may be seen as an extortionate price and gain you some troll mails.
I prefer to 'close the gap' in some markets, especially Trade Goods like herbs, ores & enchanting materials. I look for an item that has a fair few auctions listed at a spread of prices & look for the big gap in the item price. It's often possible to buy out the lower priced items & just relist them immediately at the price at the top of the gap. I guess you could say I 'buy low, sell higher' - it may only be a few gold here & there but it's a great way to build a little starter cash with pretty low risk.
|Buy Low, Sell Higher|
Using the back button to get back to the summary list, I can quickly run through all the herbs in the list to see if there are any 'gaps' similar to that shown above (32s -> 1g 95s) & snatch any cheapies up too.
Now you do need to use your brain a bit here too - sometimes that top price is just stupid high & the apparent low priced items are actually at the correct price. By regularly scanning the Auction House with your Auction House addon, you will build a picture of average prices so hopefully you won't get caught out by those stupid high price items. If you're not sure of something, especially if it's a more expensive item than just a few herbs, don't forget you can check The Undermine Journal for your server. It will show you an average price & a graph of most recent prices - both of which will help you judge the local market price for your item(s).
The most important part of playing the Auction House is to use your own brain - it's great to read tips from blogs like this one but I can only speak for my own server, you have to apply the tips & tricks to your server & decide for yourself if you want to follow my methods or develop your own. The other part of playing the Auction House is time - it takes time to learn the trends & prices & peculiarities of your server but it also takes a whole chunk of time to reach the big numbers of gold. Be patient & don't forget that even a few extra gold here & there (as shown above) all adds up eventually.