What is the best way from the Dublin Airport to the Marino Institute of Education?

The easiest way would be a taxi, but you could take any of the airport buses (16a, 33, 41, 41c) to the junction of the Swords road and Griffith Avenue and walk about 1.25km, or get the airport buses into town and pick up the 123 bus outside Eason's on O'Connell Street. Taking the 123, you should get off just as the bus turns from Phillipsburgh Avenue on to Griffith Avenue, near the gates of the Charlemont housing estate. The Marino Institute of Education is the large white building you will see to the right of the Charlemont estate.