Some generalisations/rules that help me:
The overriding factor is if you like a strong peaty/smoky/tarry character. Cos if you don’t you will find a lot of the “Island” recommendations vile: Lagamhullin, Laphroag, Taisker, CaolIsla, Bowmore, Ardbeg, Brora etc. My friend Paul is in this category.
Then decide if you like strong toffee vanilla notes (usually sherry finishing): Macallan, Glenmorangie and many others. Port finishing is interesting to: definitely winey.
The remaining spirity fruity “ester” flavours are more subtle so tend not to cause offence either way: Many of the Speysiders are like this.
The older the better as cask ageing removes the harsher spirits, leaving it smooth and palatable. I suspect the spirits have a minimum age that they become nice and it varies from still to still. I found this quite noticeable in the ‘fiddichs. I find the 12yo harsh, but the 18yo smooth and complex.
I hope this helps.