Now I gathered some of my decoupage boxes I made in the past few years for Christmas. I hope I can inspire you with this.
The preparation of a decoupage box is always the same if you use paper napkin:
The place where you want to put the motive should be light-coloured: white or cream.
Use always the top layer of the paper napkin.
Start the gluing from the middle of the cutouts. From the middle to the edge with gentle movements. At decoupage technique you have to glue the top of the cutouts, not the backside.
Use flat brush! You can use your fingers if it’s necessary - I do the same always :-)
If you are beginner try with small cutouts.
If the motive dried you can paint the box with darker colours around the motive.
In the end you have to put at least three coats of lacquer. I use Schmincke gloss lacquer.
My other blogposts on this subject: