I found these knee high socks at Target (adults). It's really simple to turn them into tights for your little one. First, have your little one put them on. Match up the heels and pin where the excess is.
Flip them inside out and mark where the pin is. Remove the pin. Using your mark as a guide draw an arch of where to sew.
Sew along the line,
and trim off the excess (I kept my scraps for another project)
Repeat to other sock.
Take an old pair of tights, or a cheap new pair :) and cut off the legs.
sew on each leg, taking care to sew them facing the same way :) And viola, you have a new pair of tights.
They look a little funny until they're on, but no one can tell what's really underneath.
and really no one should be looking, but it's there....
Now she's ready for her Valentines party.