I could have categorized this tip under "Getting around in Dublin" but cycling in Dublin is not just another way of getting around, it is a sport indeed! A real challenge even.
Pedaling your way through the traffic is a true survival. As a friend of mine once put it: "When I arrived at work after a 30 minute bike ride I was actually surprised that I was still alive and unharmed..."
Equipment *a bike (DUH!) with good brakes and preferably a bell to alert pedestrians/other cyclists that you're coming through;
*reflective/fluorescent cycle gear (vest, belt or things for around your legs - anything really to make yourself visible at all times). I used to call mine a Garda belt as I felt like a Garda (Irish police; always dressed in fluorescent yellow) in it...
*good tyres and a pump, as those poor tyres will have to cope with shattered glass and other sharp objects lying around;
*a strong heart - and even then you'd be surprised at how easily one can get a heart attack... Expect things like hooting cars/buses/trucks, huge holes in the tarmac just when you're not looking and motorised traffic suddenly steering so close towards the kerb that you'd have to jump your bike up the pavement to avoid being crushed;
*most of all, you need patience, and loads of it. Zigzagging your way between parked cars and pedestrians determined to keep walking on the cycle track is very time-consuming (and it ruins your good humour too, believe you me!).