In primary school, I'd give a card to every one in my class, and that would read:
"To [their name],
[pre-printed card message]
From Shaleen"
I did that all until secondary school, when I only gave cards to people that I spoke to and they would read the same.
But I'd do the same for close family too, and close friends.
I never used love because I always viewed the word love as something used only for romantic partners. To me, it was weird when I saw people telling their parents they loved them. Obviously I know different now.
I saw this upset my mum (I don't remember ever telling her I loved her unless she was drunk and crying to make her feel better and make sure she didn't hurt herself), and I saw that my friends all wrote "love" on their cards.
Then one year, there was a boy I liked, and I wanted to write "love" in his card, but thought it would be to obvious if I put it in only his (at first I thought "he'll be the only one that sees it" then I remembered that everyone looks at each others cards in my school) so I put it in everyones.
Everyone gave a good response, some people were a little weirded out, not because I put "love" but because of the face that it was me that did it, and I was not knows for touchy-feely-mushy stuff.
Now I always do it, because I know it makes people feel better. Now it's:
"To [their name],
[pre-printed card message]
Lots of love,
Shaleen"
Personally, I don't see the point in cards, a simple "Happy Birthday" or "Merry Christmas" is fine. Though, I've kept as many cards as I can all the way as far back as 9! That's 10 years worth of cards! and Christmas cards!