Great advice above. I would also add: don't force affection and cuddling. Make sure your pup doesn't feel trapped. Always let her feel like she can choose to walk away.
I believe this was key in my boys becoming super affectionate. They do it on their own terms. I often pick them up for just a second, give them a kiss, let them down and say, "Oooh, thank you." They come back for more.
