Hi Claire,
It depends on the situation to what I'll do. Samma's sleep patterns are changing now she's in middle age. Sometimes she's actually barking & whimpering in her sleep.
I'll sometimes blow gently on her & she'll move on in her "dream" and get quiet again.
If she's lying next to me in bed, I'll nudge her with my foot to change position (like my esteemed spouse when he's snoring). She'll stop then, but stay asleep.
Other times, I'll actually speak quietly and tell her to "get it, get the kitty cat." She'll come slowly awake and look at me accusingly like "Hey, what's the deal?" If it's a bad "dream," I'll tell her "It's ok, leave it" and she'll actually relax.
When Pepper became stone deaf, I used to do the "blow gently" on her face and she would come awake with a wag & a sleepy smile (really, she could grin). This would work better than trying to touch or shake her awake. I did this when we came home from somewhere or when it was time for her to go out. I think it's the best way to wake a dog, if it responds like that. But it's up to you to figure out what works best in your situation. Try them out, just respect that she's really deeply asleep.
Anything is better than the cold wet washcloth my mom used for my stubborn brother :D :D
toodles