I travel frequently and check fares very frequently. Fares are at an all time high but those tips are not very good. They may apply to very specific examples but largely I've found the following to be true.
The tips should really be:
If you find a good fare on a brokerage website, the deal at the home website for the company will almost 99% of the time be better.
You do need to check several websites but most often the discount carriers are not even part of sites such as travelocity, orbitz and yahoo. You need to go direct to the discount airfare website.
Travelocity, yahoo and orbitz will come very close to each other but if you check other lesser known sites you might find deals.
I just watched a show this morning where they were trying to tell people that booking ahead is a myth. I don't know how much the airlines are paying them to tell people this but it isn't a myth. If you are really super flexible then you MIGHT be able to find something, but it's usually a sub-par deal that others didn't want to take and that's why it's cheap. The best bet is always to book ahead unless you are a retiree that can drop everything and leave on a Tuesday at 4am for two weeks because the deals blackout all reasonable travel times.
The exception is if you sign up for the airlines fare breaks email alerts where you can get the latest and best deals updated to you on a regular basis. In the peak months there is no good deal to be had but in the off months you can find cheap fares. I had a couple weeks where the deal was to fly from Chicago to Kalamazoo Michigan (a three hour drive) for $189.
A good example is that the airlines do cheap fares to the Caribbean all through the hurricane season. Anyone want to go? I'll pass.
I really liked the one about cookies interfering with searches... that is nonsense and it has never happened to me. Actually fares from individual carriers can change very quickly and your best bet is to be prepared to buy a fare when it comes up... don't wait till tomorrow because the fares will change and usually it will be up.
It might have been good to tell buyers about the trick deals that advertise a low rate and then there are no seats available on the flight.
Or that the low rate is the red-eye and all the other flights are booked. Or that the combinations of departure and return dates are blacked out.
There is also information out there about when airlines each put their fares up for reduction (which is more of what I thought the article might be about because I consider that a good secret to know). I believe that American does this on Tuesday nights so your best bet is to log in at midnight on Tuesday. That kind of information would be useful.
There are a ton of other "secrets" but the reality is that it's much more expensive to travel this year and it's pretty hard to avoid the expense if you want to have control over your travel dates and your expectations.
