The most common mistake made when starting research online is surprisingly counter-intuitive: too much precision. The fact is, the more detail you include when you query a genealogical database, the less likely you are to find anything useful.
Just think. You know your Michael Barrett was born on March 17th 1868 (March 17th, St. Patrick’s Day, being the most common birthday for the nineteenth-century Irish), married Mary Murphy on September 14th 1890, had children John (1891), Mary (1893), Michael (1896) and Delia (1898), and lived all his life in the townland of Ballybeg, Co. Mayo. Carefully enter all of this into a search form and you are guaranteed to find nothing.
All it takes is a single non-matching item: in the originals, (the page recording Michael’s birth was used to light a fire in 1898); in the database transcripts (the transcriber had a late night and dozed off over the marriage record); a single item misreported by the family (John was actually born in 1890 and there are four Ballybegs in Mayo). The response from Mr Smarty-Pants Database will be the same for all: No Match.
Don’t get me wrong. Knowing these details may eventually provide evidence to unlock the truth. But to start off, you need to cast the net as wide as possible. How many Barrett births are registered in and around all of those Ballybegs between, say, 1864 and 1870? How many Michaels? Can you identify the precise marriage registration, using only the names, not the reported date? What are the ages given in the 1901 and 1911 censuses? Do they match each other, or the ages you think you know? (Unlikely.) Are there other Barrett households in and around Ballybeg in 1901 and 1911? Any with heads of household of an age to be siblings of Michael ?
The biggest sites – ancestry.co.uk, FindMyPast.ie, irishgenealogy.ie – all funnel their users like this, starting off broad and ending narrow, because it’s by far the most productive way to use their records. Their search interfaces force you into it. They know what they’re doing. They know their databases are stupid.
If you’d like an even more ranting version of this, I’ve gone on (and on) over at YouTube.