How to Make an Origami Heart
To make an origami heart, start by folding a square or letter-size piece of paper into a pyramid shape. Then, fold the sides and corners of the pyramid until you're left with a diamond shape. Once you have a diamond, fold the top flap down and tuck the corners into it. Finally, fold down the 2 points at the top and tuck them into the same flap to finish your heart.
Get a letter-size (or A4) piece of paper. You can also use a square 6” x 6” (15 cm x 15 cm) piece of origami paper. Thinner paper is preferable as thicker paper is harder to work with and doesn't always stay folded. Avoid using small pieces of paper on your first try, as the folds will be more difficult to make and this may be frustrating. If you'd like to make a larger sized heart, use a larger piece of paper. If you decide to draw a design, split it in half; it will end up in the center of the heart. A decoration can be added when the heart is finished as well. Turn the paper to the side that is white. Then, fold the top right corner downwards so that it meets the left side of the paper. Unfold it, and do the same thing to the opposite corner; do not unfold. If you are using A4 paper as opposed to origami paper (which has a white side), don't worry about turning the paper to the side that is white. Fold the bottom part of the paper in half. Do this so that the white (or inside part of the paper) doesn't show anymore. Make sharp folds by sliding your nail over each fold. Neat, sharp folds will make your final product look better. Unfold the top part of the paper. You should now have two diagonal creases on the paper. Make a horizontal fold. Fold the top part down horizontally, so that the fold crosses the intersection in the middle of the paper. Then, unfold it. Turn the paper over again. Take the left and right sides of the paper (where the horizontal crease is) and pull them toward the center of the paper. As you pull them, the other two creases should be folding, too. Pull the two sides inwards so they touch. It can take several tries to create the pyramid shape, especially if you are new to origami. You should end up with what looks like a triangle sitting on top of the rectangular portion at the bottom. Fold the bottom left corner of the top triangle so it meets the top point. Only fold the top layer, not both layers of paper. Make the same fold on the other side; you should now have a diamond shape. Fold over the sides to meet the diamond. Grab the left side of the paper, and fold everything that's not part of the diamond you made in the previous step toward the center. Do the same for the other side. Create a vertical crease. Fold the entire thing in half vertically, then unfold it and turn it over. Fold up the bottom corners. Take the two bottom corners and fold them upwards, so they meet at the center. Fold them so that what was once the bottom edge lines up with the vertical line running down the center. Fold down the top flap. Fold the large triangular flap at the top downward, as far as it can go before running into a horizontal line. At the top there should now be three individual flaps, two small ones and a big one. Fold the big one down. Tuck the corners. Tuck the two corners that you folded up from the bottom into the space inside the triangular flap. Fold down the top points. Fold the two remaining top flaps downwards at an angle. Tuck the corners again. Tuck the corners of those flaps into the space in the big flap. Check the finished heart. You should now have an origami heart. 
Get a letter-size (or A4) piece of paper. Turn the paper to the side that is white. Fold the bottom part of the paper in half. Unfold the top part of the paper. Make a horizontal fold. Turn the paper over again. Fold the bottom left corner of the top triangle so it meets the top point. Fold over the sides to meet the diamond. Create a vertical crease. Fold up the bottom corners. Fold down the top flap. Tuck the corners. Fold down the top points. Tuck the corners again. Check the finished heart. 