You will need some extra diamonds to fill in the gaps around your stars that will be the background (green drawings- if you squint, you can kinda tell they are in the shape of diamonds... Lol). You want enough extra diamonds so that you can trim (blue line) off the extra and you are left with a straight line.
Since you already have some diamonds cut, you want to figure out what size they are. Measure across the diamond (straight edge to straight edge) mine happen to be 3".
What ever the size, you want to cut a strip of fabric from your background yardage that measures that width.
Then you want a ruler that has a 60° line on it. Place that 60° line on the edge of your fabric strip (I leave my strip folded in half that way I cut 2 diamonds at one time). Make sure the edge of your ruler is not over your selvage.
Give it a cut.
Since my strips are 3" wide, I take my ruler and line up the 3" line with the newest cut edge of my fabric. If your fabric strip is 5" wide, then you line up the 5" line of your ruler with the newest edge cut edge of your fabric strip. **Wish I knew how wide your diamonds are! **
Once you line it up, you cut.
Now you have a bunch of diamonds. Lay them out as you would want your finished quilt to look like once you are finished piecing them together. Even lay out your diamonds that you will use as your background.
You could work with sewing 6 diamonds together, but I think 3 is easier.
Starting on the edge of your layout, pull out 3 diamonds that form a hexagon shape.
Take ONE diamond and mark the corners with the size of your seam allowance you sew. If you sew a 3/8" seam, mark that, if you sew 1/2" seam, then mark that... As long as they are all the same...
I don't like marking all my diamonds, so I will place some painters tape on my machine and draw a line were I will place my point, and draw a line where I will stop.
To do that, place your machine needle down in the X you have drawn for the corner of the small angle of your fabric. Draw a line on the painters tape (green arrow) where you will place the small angle tip of your fabric each time.
Then move your needle to the X you drew for the wide angle. And draw a line on your tape (blue arrow) for the stop point of your wide angle.
You will want to always start sewing at the smaller angle (blue line) of the diamond and stop at the wider angle (green line) of the diamond. The reason for that is you have more control and grip on your fabric pieces as you sew. Another way to think of it is you are always starting on the outside of your Y and sewing towards the center of your Y.
You will also want to do a backstitch/tackstitch at the starts and stops of each of your seams.
Ok, machine set up, back to your 3 diamonds that are in the shape of a hexagon. I've put a number on mine to show you which piece I am talking about; 1, 2, 3...
Starting your first seam, between diamond #1 and #2. Flip diamond #1 over onto #2. You will want to make sure right sides of the fabric are together. You also want to make sure your wide angles (green lines) of both your diamonds line up.
Line up the small angle of your diamond with your painters tape mark, sew your seam down to your stop point. Don't forget to backstitch/tackstitch.
Lay you sewn piece back on the table with diamond #3. Now we will sew the seam between diamond #1 and #3.
Flip over diamond #3 onto #1 and roughly pin in place. It is a way to remember where you will sew while you deal with diamond #2.
We want to tuck diamond #2 out of our way. So we lift up diamond #3,
Flip over #2 and fold it back in half.
Now you want to remove the first pin, line up the wide angles (red arrow) of diamond #1 and diamond #3.
Place on your machine as you did your first seam. Line up your small angle point with your line on your tape.
Sew down to your stop. Don't forget to backstitch on your start and stop.
Pull out your pins.
You now have 2 seams and your 3rd seam ready.
You want to tuck your diamond #1 out of your way (by folding it in half) as you sew your seam between diamond #2 and #3.
Place on your machine and sew as you did above, backstitching at your start and stops.
I wanted to point out that you don't want to sew past your stop spot onto your tucked away piece. You want to sew within one stitch lenght to your stop. You should be able to feel the fold of your tucked away piece and stop right before it.
Now to press your seams in a spinning fashion. The spinning seams force your points to line up, so those are super important.
Want to give your seams a finger press away from you. Make them all the same direction. Press, rotate to the next seam, Press, rotate, Press.
Flip it to where the seams are facing up and you can see the work of your finger press. The seams are all somewhat laying in the same direction.
Hold all 3 seams down with your fingers and you see the center seam intersection start to fold out like a flower. Use your finger to press a good crease. Then you can use your iron and give the block a good overall press. If they don't unfold like a flower, you might want to check to see if you sewed over one of the pieces that was tucked away.
Now you have a hexagon. I would make all my hexagons before joining them together.
Joining the Hexagons...
Joining them is very similar to the diamonds, you have your 3 seams.
You want to flip over hexagon #1 onto #2.
If you have pressed all your seams in the same direction, you will notice your seams will nest. Seam from hexie #1 (yellow arrow) will point in one direction, and the hexie #2 (red arrow) will point in the other direction.
You want to slide those seams as close together as you can, and nest them. I always pin my nested seams so they don't shift. Once I have the machine needle down over the seam, I will remove the pin.
Sew the seam, the same as above, lining up your point with the line on the tape.
Open out on your table with the 3rd hexie.
Flip over hexie #3 over onto hexie #1 and roughly pin in place.
Like with the diamonds, you want to tuck your hexie #2 out of the way. Lift up hexie #3 and fold hexie #2 in half and out of the way. Pin #2 in place.
Nest the seams between hexie #1 and #3. Pin in place and sew your seam as above.
Now to sew your 3rd seam between hexie #2 and #3. You want to tuck hexie #1 out of the way.
**One lady in my class felt it was easier for her to pull the hexie out instead of tucking it in.**
Nest your seams and sew your 3rd seam.
You want to press your seams the same ways as before. You know you have it right when all the seams are spinning in the same direction.
These guys will want to untuck themselves and that will be okay. I untuck all of them, makes it easier when piecing the hexies together.
The 6 pointed star should be forming for you...
Continue adding one hexie at a time, first orange, then green, and so on... til you have two rows of hexies together. Nesting your seams as you go.
I'm going to switch pictures on you because I don't have enough scrap diamonds to make a whole quilt... Hopefully it will show you how you would keep adding one hexie til all your hexies are together.
You will still be sewing seams that have a start and a stop, they just may not be in the shape of a Y. Start with the red lines, then add the next hexie (green lines) and so on. I did it the hard way and tried half hexies on the ends, but believe it is easier to just trim off the excess to make a straight line.
Your seams may want to take on an every other direction as you place more hexies together. But if all your diamonds are in the same direction, let the hexies take on their own direction based off the seam from the diamonds...
I hope this helps...