I decided to make a practice Sawtooth Star block before I embark on my bigger project, an entire quilt.

First I cut out the pieces. They were really easy to cut compared to a lot of other blocks because most of them started out as 3 1/2 inch strips.

 
From these 3 1/2 inch strips I cut:

four  3 1/2" squares in white

four 3 1/2" X 6 1/2" rectangles in white

eight  3 1/2" squares in Windham Fabric Feedsack II collection Yellow

I also cut:

one 6 1/2" square in peach

The first step in making a Sawtooth Star is making 4 "Flying Geese" blocks which will eventually be the points of the star.

This is a Flying Geese block, by the way.

To begin, I used a tool called a Hera Marker to crease each yellow square diagonally from corner to corner.  It's a knife-shaped piece of hard plastic that marks your fabric without using ink. You use it like a fabric pen. I think it's based on a really old tool made out of whale bone.

So after I marked the diagonals of all my yellow squares I pinned four of them - like so - to the white rectangles, being careful to match up the edges.

Then I sewed down the middle, on the crease I'd made with the Hera marker.

After I'd sewn each piece, I cut 1/4" away from the sewn line, and ironed them open.

Then I repeated the pinning and sewing and slicing and ironing for the other side of the white rectangles.

Piecing goes a lot quicker if you "chain piece" and start with a "lead fabric".

A lead fabric is just a scrap that you run through the machine before you put your actual project in it. It catches the messy ends of the thread and also lets you know that the machine is working correctly before you stick your beloved project in it.

To chain piece first sew across your lead fabric. Don't pick up your foot or cut your thread once you're done; simply sew your next piece immediately afterwards.  Do the same with all your pieces, one after another, being careful not to actually sew them together but leave a few chain stitches in between.

When you're done with your "chain" all of your pieces will be strung together. To me, when they're in this state, they look like those Tibetan prayer flags people hang in front of their houses.

Snip the thread between them and iron as usual.

So now I had 4 Flying Geese blocks and I laid out my other pieces like this

and the rest of the piecing was pretty simple.
I sewed the pieces into 3 strips

and then sewed the strips together.