Basically, the body and arms are rectangles.
For the body you would take a tape measure and measure the distance around your stomach allowing for an appropriate overlap(the amount is basically up to you) The hight is one inch from the base of the neck down to where you want it, but I would recommend it ending above or right at the knee. Then you'll measure the distance from center armpit around the back and back to the center of your other armpit. Take this distance, and divide it by two, this is length A. Then take the top of the body piece and find and mark the center. From this, use measure A and mark on either side.
Your next step is to measure from the edge of your shoulder to about an inch from your neck, this length B. Then find the mark made from length A and go down 2in. If you're a big guy 2.5 and if your really big 3. From this, you will take length B and find the angle on both sides of the mark where it ends up being 1 in from the top. Then draw this, making a straight line from the endpoint up to the edge of the body piece(which should be one inch) Do this on both sides of each mark. Next, measure the circumference of your arm from the top of your shoulder, divide by half and add about 4 in. This is length C. Length C starts from the top of the body piece at each marker that was found from length A, and goes straight down. Please look at the pic.
This completes the body portion. Next, the arms.
The arms are measured from the edge of your shoulder to where ever you would like to end and add at least one inch for seams. You can add more if you would like cuffs. Then take a tape measure and at your wrist, make a loop that seems comfortable and hangs loosely (about 3-4 in down from your wrist). Add 1in. for seams and this is the width of your sleeve. If you ended here, you wouldn't have enough sleeve for your shoulder, so you will have to add a triangle called a gusset that will go underneath your armpit.
So, do the same thing for the shoulder as you did the wrist, making the loop dangle loosely. Take this measurement and subtract the width of the sleeve. Add two inches to the difference and that is the width of your gusset. The length is however long you would like it, but probably a little shorter than the distance from your shoulder to your elbow. Make a T shape with the width and the length and connect to make a triangle. This is your gusset.
Now you can continue to cut the hood, or you could sew the body together. Its getting late, so I'll tell you how to cut the hood tomorrow. To sew the body, you'll first sew one of the sides of the gusset(its an isosceles triangle so sew one one the congruent sides) to one end of your sleeves. The point of the triangle should be pointing towards the other end of your sleeve. Next, sew the other side of the gusset to the other sleeve, starting from the end of the sleeve moving in. When you get to the end of the side and meet the other side of the gusset, continue up the sleeve until you make a tube.
Then take the body, and cut out the triangle shaped pieces you marked out, and cut the line you drew for length C. After this, fold the ends until the cut for length C are on the fold. Sew the edges from the top all the way to the cut for length C on both sides. Then insert the sleeve from the inside(so when you turn it inside out you wont see the seams). You may have to extend the cut for length C to get the sleeve to fit, but that's normal. Then go ahead and sew the sleeve in.
I hope this makes sense. I always go to the thrift shop to buy some sheets to cut up first for a pattern. I pin that together and adjust it until I'm happy. I'll write about the hood tomorrow. If there's any questions, just ask
Scouter
Oh, btw, I normally do 1/2 in seams.