We've been going to sing and sign classes, which I would definitely recommend if you have them near you! But yes, just keep signing when you say the word to them, and they'll eventually do it back. We started when she was 9 months - baby girl now signs a lot and can communicate so well, so it's so worthwhile!!
We do makaton, so we watched singing hands for a bit of an afternoon as they sign and sing and at nursery my little boy has started to sign please, thank you and more
Yes! For ages it felt like it wasn’t working but then randomly he started signing for milk. He now also knows ‘more’ and ‘all done’ although that one he won’t use as consistently. Keep tying and hopefully she’ll pick it up soon