When taxiing at an airport without a full-blown airport diagram (most commonly, a non-towered airport), how does a pilot know whether taxiway A (Alpha) is on one end of a runway, or the other? Or, in the case of taxiway exits, how does one know whether exit A1 is at one end of a runway, or the other?

In other words, are taxiways numbered in a predictable or consistent way? An example would be, “Exit A1 is always located at the easternmost exitway of Alpha”. If they are, is this because of custom or regulation?