1. Purchase your local newspaper - e.g. for Fingal it's the Fingal Independent, for Drogheda it's the Drogheda Independent etc etc. Many new developments coming on stream now have conditions attached for local needs only, thus expressions of interest are invited by advertising in the classified section.
2. Register your interest with your local estate agent - Stay close to them, in particular the ones that seem to specialise in new developments. Update your requirement every 1 - 2 months, this way they will know you're not a timewaster & your details are updated in their database. When new developments are launched they normally only send to the last enquiries for X number of months so simply registering your interest isn't enough.
3. Take a close interest at Planning Applications in the area you want to move to. Very often you will see what is planned and the developer who is building. Many developers have loyalties towards particular estate agents so you can almost predict who will launch a development and target your interest there.
HTH