Place a square of heavy-weight, colored paper in front of you on a flat surface. Fold the top edge down to meet the bottom edge and unfold it. Fold the right edge over to meet the left edge and unfold it.
Flip the square over and fold the top left corner down to the bottom right corner and unfold. Fold the top right corner down to the bottom left corner and unfold. Flip the square back over to the other side.
Collapse the square by pushing the left and right horizontal folds inward until they meet underneath, with the center point sticking up. Squash the top and bottom of the square together; you should end up with a flat folded triangle.
Fold the top layer of the left point over and up so it touches the top point. Fold the top layer of the right point up to the top point. Flip the triangle over and repeat this process, folding both points up to the top point. You should end up with a folded diamond.
Fold the left corner of the diamond's top layer inward to touch the middle line. Fold the right corner in to touch the middle line. Flip the diamond over and fold the left and right points inward to touch the middle line.
Fold the top left and right flaps down so they touch the middle. Tuck the left flap into the hole directly underneath it on the left side. Tuck the right flap into the hole underneath it on the right side. Flip the shape over and repeat this process on the reverse side, so all four flaps are tucked into their designated holes.
Pick up the origami shape, letting the sides loosen and unfold a little. Locate the hole at the bottom of the shape and blow into it to expand the origami into a roundish fruit shape.
Turn the origami fruit over so the hole is at the top. Leave it as it is to make fruit with little or no stem, such as an orange, lemon or blueberry. For apples, pears or other stemmed fruits, clip the top layer on one side of the origami with scissors. Cut down towards the middle of the side to free a flap, then fold the flap up to the top to represent the stem.