Before attempting any sort of origami art you need to understand the two types of folds used in origami, a valley fold and a mountain fold. A valley fold is a fold where you fold the two sides of the paper towards you and when opened, the paper looks the same as a newspaper does when it is opened. To make a mountain fold, fold the two sides of the paper away from you so that when opened, the paper looks like a book turned face down with the crease sticking up into the air.
To begin, get a square piece of paper. If you do not have a square piece of paper readily available, get a regular piece of paper and cut off what is needed to make it square. If you are going to actually use the star as a decoration you may want to purchase decorated or colored paper.
Once you have a square piece of paper, hold the left corner of the paper and valley fold it diagonally and unfold it. Now valley fold it again starting with the right corner and unfold it, the creases should make an X on the paper if the folds are made correctly.
Now valley fold the paper in half, unfold it, rotate the paper and valley fold it in half again so that the 2 new folds make a cross. You should now have a crease across the middle of the paper, from top to bottom and from corner to corner.
Refold the paper diagonally (starting at the left corner again) and leave it folded this time. Valley fold the left corner of the triangle so that the fold falls on the nearest crease and then mountain fold the right side of the paper so that the fold falls on the nearest crease on that side.
Now comes the technical part; hold the tip of the valley fold you have just made and bring it across to the right side and take the tip of the mountain fold on the right and bring it across to the left. Basically the 2 folds should switch positions and you should see the bottom 2 points of the star with 2 more points above if this step is done correctly. There should be a pre-made crease nearby to make this step easier, press the paper firmly to make the folds stay in place.
Take the left point and valley fold it down (there should be a crease here) and then fold it back up making a new crease so that ¼ – ½ inch of it is still folded down while the rest is folded up to make the left point of the star. Repeat this step on the right side of the star and your star is completed.
If you did not make the creases firmly enough throughout the process the star may not hold together properly but a bit of glue or tape will probably remedy this.