2.  Music
With all the greenery you have added to your garden, hopefully the birds will be providing you with their many varied chirps, trills and calls.  But to add a little bit more magic, definitely include a wind chime ... or two or three!  The calming melodies, resulting from the slightest breeze, will manage to slow down the pace in your space and literally "make the world go away".  This is important as fairies belong to another dimension, where time plays out differently to our own.  The music from birds, wind chimes, flutes or even gentle songs on the radio or other device will alert the fairies that your garden belongs to people that understand and welcome them.

3.  Trinkets
Fairies appreciate offerings from the human world.  The food they most often prefer is bread, honey and milk.  But in the Spring and Summer, so much more can be offered.  Leave out some pretty polished stones or gems, light tealights or candles and place glass marbles, orbs and prisms in various parts of your garden.  Tuck cunning little statues of their kin folk everywhere you can - this lets the wee folk know that you are a kindred spirit who believes in fairies and will take care of your garden in a fashion that does not disturb or control nature too rigidly.