From the start, i would like to make it clear that this post is going to try and give you an insight on how you should post auctions, so you don't end up "shooting" yourself in the leg with undercutting. The most usual mistake many new or "veteran" auction house posters that are using addons for their posting, is the fact that they are simply clicking the post button without checking for the competition.
For the sake of a example, i will take the jewelcrafting market due to it's volume. At the start let us make one
In one of the previous posts The Auction House Bait, i talked about how to use this constant undercutting, and generally hasty way of posting to your advantage so you can acquire cheap items, well this post should be like the exact counter to that strategy, and it should help you get better prices, or keep your prices rather high and not loose out on the profit.
After pressing that button, TSM will show you a list of all the items that are with that name on the AH at that given time. Reason why this is so important is that you can visually see the prices, and from there see if there are price irregularities, like sudden price spikes be it up or down, and act on it.
As an example i've made this screenshot of the prices of the Stormy Ocean Sapphire. As you can see, the prices were normal at around 75g, until someone used a page from the The Auction House Bait book, or simply posted a few at that price. Well this is where the people not looking at the prices and shooting them selves in the foot part comes into place. As you can see after that single post of 3 gems at 19g (marked with yellow color) the next 3 guys that posted their gems posted it lower, where they could have buy out those 3 gems and post their at 75g and keep the price.
The price of this particular gem might not be a very high one, but if you simply press that Show Auctions button and watch the prices of the items you are posting, and instead of undercutting that one guy that has undercut everyone for huge amounts simply buying him out, you end up with a good profit margin in the long run.
At a first glance it might look like a small amount, but there are items like the belt buckle ones where occasionally someone will come in and drop the prices for 100 or even 200g just for the sake of selling 1 or 2 and people will continue to undercut him opposed to buying him out and reposting his own items and robbing him of the profit. So use that Show Auctions button, and post your auctions at the right price.
So, like always, keep an eye out for good opportunities out there.