Paper.

Use an ad from a magazine for a shiny finish.

Use construction paper for a matte finish which you can paint on.

I don't recommend using scrapbooking paper since it tends to get hard to fold after a while but it's up to you.

Rip out your page.

If there's writing on your ad, don't worry. All that matters is that the CENTER of the page is clear of writing since that is where the star will be cut from.

Fold your paper in half, hamburger style.

Ignore the creases.
I went through most of the steps before I took pictures. >___>

With your ruler, mark the halfway point at the bottom with a pencil.

You don't need a big mark, just a dot that you can see.

I forgot to take a picture of this! :D

Now take the upper LEFT hand corner and fold the tip to the halfway marking you just made.

Crease.

Fold the lower left hand corner over the top left hand corner that you just pulled down.

Crease.

Fold the paper in half so the top goes back and meets the bottom.

Crease.

Take scissors and cut from the tip of the small top triangle. Basically, you're cutting that triangle in half.

It is important that you cut at THIS exact corner and at an angle very similar to this. I have received complaints that this doesn't work every time and it's mostly because people aren't cutting it correctly.

Discard scraps and unfold the piece you just cut.

Crease the points of the star so that they all pop out in the same direction.

Viola!

Nautical paper star!