I have been asked to address a specific category of person. Before I try, it must be said that on one cannot advise individuals fully until their particular circumstances are known. All I can do is lay down a few guidelines, looking at the options open to you in various circumstances. So, we spend time trying to find a record in Ireland of marriages which took place in America, or explaining how impossible it is to find Mary Murphy unless you know something which distinguishes her from others of the same name. Unless you have a very unusual name, it is pointless to proceed until that much is clear.
Some people are lucky enough to even know the parish they came from.
The temptation is to write to the pastor. The most important source of information is the church record of baptism and marriage, and he has it. The most natural thing in the world, therefore, is to write and get the information from him. It's cheaper too. If that satisfies you, fine.