1) Lay the paper down on a flat surface...table, lap board, hard floor, etc.
2) Fold the paper horizontally. Match the top corners to the bottom corners. Crease with your fingers. No need for a bone folder, since you will be ironing these creases out later. This will be fold #1
3) With the paper still folded, fold the piece vertically. Match the left corners with the right ones. Crease with your fingers. This will make fold #2.
4) With the paper still folded, fold it in thirds diagonally. You will bring the left fold (#2) over midway on the right side. The corner should extend past the edge a bit. Crease fold. This will make fold #3.
5) To fold the other third, bring fold #1 over to meet fold #3. Crease fold. This will make fold #4.
6) Cut along the edge where marked in the below diagram. You will throw away (or do something else with) the top portion you cut off.
7) Open folds #4 and #3. This will make cutting easier. You will have less layers and have a more accurate design when cutting.
8) Scale the below pattern to the size of your paper, or draw your own design
9) Copy the pattern with your pencil onto the triangles created by the folds. The left side will match up to folds #1 and #3. The right side will match up to folds #2 and #4.
10) Use scissors to cut the designs on the folds, top and bottom point.
11) Use a xacto knife to carefully cut out the inner design (a heart, three dots and four petals).
The red areas are where you will cut.
12) Carefully open the snowflake and press flatish with your hand.
13) With the lowest setting on your iron and with the steam turned off, carefully press your snowflake flat. You will not be moving the iron back and forth. Just set it down on the bent sections of the snowflake for a few seconds at a time. The weight and heat will flatten the snowflake. If any details are skewed, adjust them by hand and press flat.
14) You can tape the snowflake to your window, use a paper clip to hang it or ribbon to hang it.
(Via Crafty Lady Abby)