Reducing bulk at curved seams can be done with notching or clipping.
On an outer curve, we notch. This is cutting triangles along the edge. To check whether or not it worked, pull the fabric and straighten it.When you straighten the curve, it should make a straight line without bumps. If it bunches when you straighten it and looks wavy, you need to notch more. Cut close to the seam line but DO NOT cut the seam (that weakens the seam.)
Now for inside curves you use clipping. This is cutting slits into the fabric. You don't take out any fabric, just one single cut will do. When you straighten the curve to check if it worked, there should be any pulling in the fabric and it should straighten nicely. Add more clips if there's pulling or stress on the fabric.
Reducing bulk at corners can be done with trimming and clipping.
At an outside corner is really easy to reduce bulk. To trim, just cut the tip off close to the seam. Easy beezy, done.
Clipping at an inside corner is super tricky....just kidding. You make one clip into the fabric where the corner is. Boom, done.
When you straighten these, the trimmed edge should meet and the clipped edge should straighten. Trimming when straightened should look like clipping when not straightened and clipping when straightened should look like trimming when not straightened.
Grading is cutting multiple layers shorter and shorter one layer at a time. This is for when multiple pieces of fabric meet. Leave the facing the longest, so just don't cut that one. Cut the layer next to the facing a little bit shorter than the facing. Continue cutting each layer shorter and shorter. How much you cut off depends on how many layers there are. If there are three layers, you leave the facing the same, the 2nd layer should be around half of the length of the facing and the 3rd layer should be very short and close the seam. To check, run your finger along the layers, it should feel smooth and flows nicely.
Don't be jealous of my Paint skills ;) Hope my artistic abilities helped!
And happy anniversary to Jordan and her husband!