Even if you've only done a little bit of sewing, I'm sure you've been in a situation where you're trying to pin two fabric pieces together and one piece is slightly bigger than the other.  Even when I cut out my pieces as carefully as I can, it still happens. And sometimes it happens on purpose because the pattern drafter wants to create garment shape or fullness. But what do you do in these situations?  Do you cut off the excess?  Do you just start sewing, hoping for the best, and end up with a big fat wrinkle in the middle of your seam?  I will admit to having done both of those things during my beginner days.  Now that I'm more experienced, I'm going to let you in on my little secret which is "easing."  What is easing you ask?  Well, easing is a method of taking the excess length of one fabric and trying to evenly distribute that excess throughout the length of the shorter piece as you're pinning them together.  The end result should be a perfectly smooth seam with no puckering and the edges of the fabric pieces should be aligned. There are different methods for accomplishing this and this demonstration will cover the most common ways so you never end up with a puckered seam again.