This card is 4 1/4" square. My own tutorial for preparing an A2 sized envelope for a square card can be found on my blog under tutorials or here's a quick link.
The Perfect Layers from Perfect Paper Crafting was used to create the 1/16" border. The Perfect ruler was used to cut out of the box and I often use the The Perfect Square for the same task.
Other tools: Scor-Pal to emboss the lines on the insert cardstock trim.
Memory Box cloud die, these were popped up with foam tape
EK Success - snowflake border punch on insert and I glued the punched out flakes on the seam of cardstocks with Aleene's tacky glue.
Accessories:
Copic markers: smoke - C3,1,0,00, gingerbread - E37,35,32,31, blender, candy canes and tree ornaments - R37,35,32, house trims: purples - BV04,02,01,32, yellows including tree star - Y38,35,32, pinks - R85,83,81, greens - G05,03,02, Tree - G29,28,24, trunk - C6,5,3, stepping stones RV29,25,23,21, gift - B69,66,63, ribbon and tree pot - RV69,66,63, lollypop: - stick - E15,13,11, wrapper - Y19,18,15,11, sign - C1,0,00, background shading and clouds - B21,BV000,0000,blender, shadows - C1,0,00