Agree with Carmel. Also, pick a few topics and make up something about them.
e.g. what to do in spare time, family info, schools you went to, your job etc.
I used to have a set number of 'stories' and try and direct the conversation around so I could talk about the topics I had practiced. Of course u need to be subtle about it so its not obvious what you're doing.
Also, dont be reluctant to use a few English words if you get stuck. You often hear irish speakers doing this and it sounds better than stumbling along, searching for the right word.
Go n-eiri an t-adh leat!