The guide should advance to the point where you are in the zone's progression. There are a few steps that can-not autocomplete and they should (hopefully) have comments to the effect of -- you need to manually check this step off. -- For some reason you have to click these steps off 2-3 times to work. (the first time will move the tom-tom arrow, the 2nd time unchecks it and the 3rd click advances the guide).
Be warned that players will occasionally list items in the Auction House that are sold by vendors. This typically applies to limited sale quantity items or items in remote, harder to reach locations. Items from Outland that advance certain skills (such as books for training Cooking or First Aid past a skill of 300) are typical. These items are notoriously listed for 2, 3, or even 10 times their vendor purchase-able price. Using an add-on such as Auctioneer Advanced can forewarn you of such a tactic. You should ONLY buy such items if your server is so full and busy that you simply are unable to acquire the item on your own. Otherwise, wait for the vendor to re-stock (usually takes about 20 minutes to 1 hour depending upon the vendor). You'll save yourself a considerable amount of money. See Buying Items from Vendors for Resale below for more on this.
If i start on a new realms, I am farming a lot of transmog from classic and Burning Crusade Dungeons and Raids. In the beginning, i start to post them if they have at least a DBRegionMarketAvg (Average value of an item on all EU realms of the last 14 days) of 500 Gold. All the other items get vendored. The time you hit a stock of 1000 Items, my value treshold raises to around 2.500 Gold. All the items below that value get vendored aswell. Newly farmed items that are above these treshold will be listed. Why? If I start over somewhere, I want to get a certain amount of gold quickly. Cheap items are great for that. Later on, to save time, Quality is better than quantity. As mentioned above, re-posting the items on the auction house takes quite a bit of time. At this point, I can recommend you the TradeSkillMaster AddOn, it makes your auction house work really a hell of a lot easier.