How much advice should you give to your daughter/son regarding babies and parenting?

I hace two grandchildren-one in New Zealand who I never see so advice isn't relevant-and a new grandson born in December last year.
I see my daughter and the baby at least once a week and she is always asking my advice about feeding, sleeping etc. She doesn't always like my answers though and I find it a minefield trying to be tactful and not go against my daughter's ideas of parenting.
Many of the things she does are completely different from the way I managed my babies and different again from the way my own mother brought up my brother and I. I am more flexible and easy going than my own mother who is always criticising my daughter to me about the way she fusses over the baby and picks him up at the slightest murmur.
I try always to be tactful in the way I suggest things because I am very afraid of my daughter getting annoyed with me and not wanting me to be such a big part of my grandson's life. I can see it getting harder as he grow up and discipline becomes an issue.
Does anyone have any advice/experience of how to deal with this issue? I really want to do the right thing by my grandson and his parents.