Sterla, I found it weird at the start with DD1 as she couldn't speak but then I practiced just talking to her during the day and saying it in the everyday conversation eg, kiss her toes and say I love your toes and I love you. I also read to the girls a lot and one book that helped was "Guess How Much I Love You". Reading that regularly helped me say it more naturally.

Also once I could see her starting to understand what I was saying it made a big difference and she would smile when I said it so I think it reinforced me saying it.