Well,

You'd (I'd) approach it the same way you'd approach anything of that nature (like dating someone who's never really dated, or had much/any sexual experience before).

You take it step by step... You get to know the person, their likes and dislikes and you make a judgement call as to what they can 'handle'... and you introduce them to 'stuff'...

(imho) I'd treat it the same way as with someone who's never French kissed before, or done oral, or whatever...

It's a mix and match- what she's into vs. my experience with that, what I'm into vs. her 'thoughts' on that... and just.. being sensitive and taking things one small step at a time... It's never wrong to do 'not enough' and leave them wanting more, lol.... No particular guidelines.. depends on their interests, and how they respond to some initial lighter stuff....

RE: 'First sub's experiences'- yeah, well.. that's (for me) just maybe people not understanding that (imho) D/s relationships have all the same factors in them as regular bf/gf stuff in then, -plus- another layer on top of that... Harder to find a 'close match' than regular vanilla relationships...

Plus also, probably, some 'unawareness' of the Dom, and also perhaps some 'lack of self-knowledge' of the sub... (fantasies not always being quite like real life and some 'undiscovered territory')...

And there you go-

-Rx