A basic origami which can be used in many crafting activities is the open box.
It starts with a square sheet of paper folded successively along the 2 diagonals. Re-open after each fold. You should obtain a paper square marked by a cross running from the corners.
Then, fold each corner to the middle of that cross to get a smaller square. To make sure you did it right, unfold everything to see if you get a sheet of paper marked like on the 4th following drawing.
From the square with the folded corners, fold 2 sides of that square toward the middle.
Re-open those 2 folds. Fold the 2 other sides. To check if you did right, unfold everything. You should get the initial square with all the following marks.
From the initial square, fold 2 opposite corners towards the middle. Fold them another time, again towards the middle.
Choose one of the 2 non-folded corners and fold it backwards, following the blue dotted line on the following drawing. You obtain 2 right-angle corners.
Imagine a square to which these 2 corners belong. Fold successively each one of them along the diagonal which runs through the imaginary square. Unfold them.
Once you've folded the 2 corners, unfold the corner of the initial square (the one folded backwards) too.
Use the other initial corner and redo the last 4 steps.
By slightly unfolding the 2 other sides/corners (the ones folded towards the middle), the box should start forming. Simply orientate the tops of those 2 sides/corners towards the middle and wrap the unfolded corners around.
With this kind of box, a bit a wood and colour pencils, I chose to craft an Advent calendar. This is the result.
