I see that the early rule isn't really used any more (I'm sure I stopped using it before), so here goes...
As a general rule of thumb, away from very large settlements (circa 250,000 and above), stations that share the same first letter as me perform fairly poorly in patronage figures, in spite of my letter - itself part of at least one digraph in the Welsh language - being quite a common first letter. However, by that lousy standard I am fairly large, although even then there are larger stations fairly close by in both directions on my solitary route, which is double-tracked and not electrified. I am within 50 miles of the border between England and one of Scotland and Wales and have services to both England and the other part of the United Kingdom. I have a fairly regular service but my frequency is not entirely standard; I tend to get two trains an hour each way on weekdays but this can vary, and a small number of services pass straight through. Lastly, the next station to the south shares the same first letter as me, but it has only one instance of the letter, whereas I have two.