You can find licensed taxis at any appropriate taxi stand or in the street by waving one down. They are marked by a yellow “TAXI” sign on the top of the car and run on a meter.
Hackney cabs, on the other hand, need to be ordered by phone or in person at a local hackney office. Hackney cabs are generally unmarked and prices fixed depending on the destination. You can, however, try to negotiate a cheaper price. Be sure to turn on the blarney.
Peak hours in Dublin are similar to those of the rest of Europe, between 7:00-9:00 and 16:00-19:00 from Monday-Friday. It is also harder to get a cab in the evening and at weekends when the pubs close. So bear that in mind as you contemplate taking a jacket out with you. There’s nothing like a long wait in the rain to put a damper on your evening.