This isn't hard because most Christmas traditions already have a spiritual meaning. The problem is we take the time to DO our Christmas traditions, but a lot of times we don't take the time to explain why we're doing them to our children. A GREAT book for helping children find Jesus in our holiday traditions is The ADVENTure of Christmas by Lisa Whelchel. There are 25 different sections, so you can cover a section a day starting on December 1st. For example, did you know that an English missionary was the first person to use the evergreen tree as a symbol for God? He referred to it's triangular shape and said that it represented the trinity. Also, we know that Jesus died for us on a cross (from a tree) - remind your children of that.
From Lisa's book - Have you ever noticed that the boughs of your tree extend out like the arms of Jesus stretched upon the cross as He offered His life to anyone who would come to Him in faith? And your Christmas tree is very definitely pointing toward heaven and, as Jesus did with His words and His actions, drawing our attention to the Father who loves us.
Take some time with your traditions and find a spiritual lesson for each one. Your children will remember why you do the things you do for Christmas and they will remember that each one reflects Jesus!