It is easy to get lost in the time to create sources and citations - been there, done that. You will change your methods part way through, so don't aim for perfection from the start.
So here are a few mental tests to apply:
- Can someone find the same entry again on the same web-site?
- Can someone find the same entry in an equivalent source? (By which I mean, if you're citing a PR on FindMyPast, could I find the same entry in a microfilm of that PR held in a Welsh library somewhere?)
- Have you warned people about possible pitfalls in your source? (For instance, if you've got a transcription of the original PR, which might have transcription errors, have you warned people that's what you used?)
- Can you find the same entry for the Source again in Ancestry's tree system and re-use it usefully?
- Have you got any pointless repetition (For instance, if you say Author = FindMyPast, Publisher = FindMyPast, Repository = FindMyPast - do you really need all those repeats? Possibly 2, possibly 3, but not always...)
So - to your example... Please note that my attempt will be different from yours - that doesn't mean one of us is wrong. Note also that I am just talking about a Source in Ancestry's tree system. First I need to decide what my Source actually is. A good rule of thumb for me is that if it's a "photographic" image of the very original, then I source and cite it as if it were the original, just adding the extra data (to say that it's a microfilm or digitisation) into the publication data. If, on the other hand, it's a transcript or index, then the possibility of errors is such that needs to be made clear upfront by adding that into the title of the source.
You have "Glamorganshire Baptisms" (on FMP) as your source. I'd be inclined to invest a bit more detail in the source - "Glamorganshire Baptisms" is a collection on FMP and that won't help the guy going into the library looking for a microfilm. So how about saying that your source is the Parish Registers of St. John, Cardiff? (Notice this is in the plural - another option is to identify exactly which PR of St. John, this is, e.g. Parish Register of St. John, Cardiff, Baptisms 1875-1921 (making it up here) - but this is liable to be tricky to do. FMP seldom help you to "walk" the pages of a register to identify which it is).
So, Title = Parish Registers of St. John, Cardiff
Author? Some people like to put the name of the archives holding the stuff. I find that pointless if it's recorded elsewhere (duplication, see?) I'd put
Author = St. John, Cardiff (Church in Wales) (Argue amongst yourselves whether I'm duplicating - I prefer to repeat the church's name to make it clear that this is their copy and not a transcript by Fred Bloggs)
Publisher = FindMyPast
Note against the Source - I think I ought to add "Images and Index of Original" in here???
Do you have to put a Repository in for the Source? I rather think you do, so I'd put FMP like you have - it just messes things up a bit if next week you need to record a microfilm for the same church...
So - on to the Citation -
I always get lost in what the Detail section is about, because their explanation is not good. What I use it as, is the means to identify exactly where in the Source you need to go to find the info.
In your case, your Detail just repeats the Source Title, which sort of seems a bit odd to me. I would put something that enables someone to find the entry in my Source of "Parish Registers of St. John, Cardiff" - remembering that they might be using a microfilm. Maybe:
Detail = "Baptism of Cyril Alexander Harris, 29 January 1913"
(This isn't the place for a transcription). You could add the page number and entry number to that Detail - up to you.
Transcription of Text - strictly speaking this is the transcript of the image of the PR in my example but I'd copy the transcript from FMP, just like you.
Web Address - and that clang that you heard is the pitfall of changing URLs opening. Basically, unless the web-site has guaranteed that its URLs won't change (like FamilySearch do - until they change), then it's a waste of time to quote URLs inside the big sites. They will change over time. And in any case, your URL might not look anything like mine. (Spoiler - it doesn't - I just compared them!) Personally, I'd just put the URL for the front of FMP and leave it at that.
OK - I wonder how much I followed my own rules? Please identify any issues.