Tools: a couple different shovels and trowels.
This pile started out large after shoveling all the snow off the drive and sidewalks the past week and made a perfect base for the heart. Next, I made snow balls snowman-style and piled them up, packing in snow in between the balls, slowing build up the sides using some wetter snow to help with the stickiness. I built a brace on the back of the heart to give it some more mass to help it last a little longer (this one's not gonna stay up long with these over 60 temps!). I smoothed it all out, packing in the smaller divits by hand and using the back of the garden shovel to smooth off the high points.
After all was done and my wife was calling me in for lunch, I grabbed a can of red spray paint and painted the heart.
My 4 year old daughter helped with piling on some snow and with some of the photos. She loves it! As well do the neighborhood kids.