I started with just doodling and came up with a doodled heart flower.  I liked the motif but it was very fussy and I wasn't sure how I could make it work as a card. 

After a bit of tweaking and playing about on Illustrator I noticed the little hearts from the outside of the motif looked like they were fluttering down.  A bit like confetti.  The pattern quickly came together from there.  I scattered them across the page and put the same motifs in the background but rotated them and put them in another colour to give the final design.

A few colour changes and I settled for the usual red and pinks for Valentines.  With a bit of hand drawn typography it's simple but says what needs to be said for Valentine's day!