The best place to search for this type of housing is on Daft.ie. This is only suitable for long term accommodation. When you find a suitable property, make sure you get your landlord to confirm in writing the length of your lease, the conditions you must meet to get your deposit back, who to contact if anything goes wrong and how much notice they need before you leave the property. Make sure you get a receipt for all monies paid, avoid paying in cash, and when you move in, take photos of any damage, so you don't get charged for it when you leave. Other private accommodation websites include Homestay and MyHome.
It is important to know your rights and responsibilities as a tenant and you can find lots of information about renting on the Residential Tenancies Board website and Threshold – the National Housing Charities website. The Union of Students in Ireland also have a great finance and accommodation guide on their website.
Warning
Watch out for rental scams. One of the most common scams is when someone copies listings of properties that are genuinely available to rent and advertises them with their email or phone number. They might refuse to show you the property, saying they are too busy or living elsewhere, but may send you photos and fake documents or keys in the hope of getting you to pay rent or a deposit. Often victims do not realize they have been scammed until they show up at ‘their’ property to find someone else living in it. Remember, if it sounds too good to be true, it probably is too good to be true.