I feel like I have cracked into Travel Hacking using Points and Miles, but not everybody feels comfortable with the whole credit card dealy. Another thing I hear often is that people don't want to spend time on searching, or they do, but just have no idea where to start. I will do my best to outline my process for helping out a friend here in this post. Hopefully you can learn something from it.
There are many many options for searching for flights. Some just search (ITA Matrix), some aggregate results (Google flights, Kayak) and others are actual Online Travel Agents (OTA) that you can book with. These below, are the ones I am most comfortable with but due to the crazy nature of flight booking, it is possible that each site will pull up completely different prices for the exact same flight. Keep in mind some airlines will not show up at all on particular search engines, so it's useful to remember that and know the low cost carriers in your destination. Whatever you do and whichever ones you use, try to search at least 3 different ones to get a good snapshot of the price. If you don't have time, you can get us to do it, or go see your local travel agent.
ITA Matrix is a super database of airfares. They don't let you buy the tickets but they do help with searching. You can search by multiple destinations and with advanced options like specific airlines, specific connections, specific fare classes, and all sorts. Travel Codex has a wicked tutorial on it. Or there's another one from Million Mile Secrets.
Using this as an example, it looks like the cheapest flights across the Atlantic are to Dublin with Aer Lingus. The ITA calendar shows us the cheapest were leaving on a Tues, Thurs or Sat and returning on Mon or Wed. Clicking through shows us there are also options via Iceland to Frankfurt for just a few $ more. You can hire us to book the flights you find on ITA Matrix or go through a Travel Agent. You can also try searching the flights directly on Expedia, or Kayak. For Advanced users, you can enter the ITA fare construction secret language using Hipmunk (see tutorial here).
Skyscanner is pretty sweet. It is an aggregator and shows you a list of results from other OTA's (Online Travel Agents) and airlines. You can search by whole country and it has flexible date options. Sometimes these show up with a little "Get Prices" button instead of a $ number, but still not bad to get a gist of the price.
Kayak is a meta search tool and uses the data from ITA Matrix. It can be a little friendlier to use though and has a cool Explore option for when you don't know where you want to go. The Explore option is a little dodgy but still gets you all excited when you see the options you have.
Google Flights is an aggregator and usually allows you to book directly on the Airline's website. It has an amazing calendar tool which displays the cheapest date to book and it even prompts you when it knows there is a cheaper flight a few days away or at a nearby airport. You can add up to 5 airports in the search boxes by airport code, and also search multi-city flights (Open Jaws, etc). You can also filter by Airline, Alliance, Flight Time, Price and Stopovers. Super handy tool.
What tools do you use? Which ones show the best results?