You need:

3 inch square wrapping paper

1 7/8 inch square cardboard as template

small piece of tesa adhesive or other brand

Make a fold in the center of each side, no longer than 1/2 inch, shown in the pic with the needlepoints.

Put a small piece of tesafilm, about 1 inch long, on one corner.

Center the cardboard square on the backside of the wrapping paper with the corners touching the folds.

Wrap the corner with the tesafilm over the cardboard, making a crisp fold with your fingers.

Repeat with the next corner, catching the tesafilm.

Repeat with the third corner, for the last flap make only the fold, take care not to glue it down now. Remove the cardboard.

Fill with your little gift.

Close the flap, rubbing the paper to the glue tape.

You are done with your neatly folded gift wrap.