Print your boarding pass before you get to the airport or you'll get whacked with an extra fee. Yes, you have to pay €40 to print your boarding pass at the airport (whaat?).
If you carry on a bag, make sure it fits within the guidelines on their website. The hand baggage allowance on Ryanair flights in 2013 is 55cm x 40cm x 20cm (21.6" x 15.7" x 7.8"). This is just a bit smaller than most standard carryon bags. Also, if you add a checked bag online the fee is €20, but if you get nailed at the gate with an oversized carry-on the fee goes up to €60! To avoid this trap Chris and I went to several stores with measuring tape to be darn sure our bags fit the guidelines. It was a struggle, but we found these bags at REI which were the perfect size (I mean, they were wicked small...).
One more tip for the ladies: you're allowed ONE piece of hand luggage, including your purse! So you must leave room inside your carryon for your purse. Ouch. How I fit almost 3 months of clothing and my purse inside this tiny bag is beyond me…. perhaps a future post on what I packed?