
There is nothing you can do really other than be there (cancel all your appointments), have her sleeping in the whelping box, with you in the room too so you know pretty much when contractions start. For me, it's when they have strong contractions, getting nowhere after about one hour, that you need to act = vet. And that applies to each delivery. There's no point leaving her to struggle, becoming exhausted (and risking the life of that puppy and all those yet to be born, and her) if she's going to need a C.Section.
With mine, and knowing some went into secondary inertia, I always phoned my vet to warn them I might need them, once strong contractions were seen.
Sounds as if you'll have your hands full soon!! Perhaps you already do.............