any tips on how to achieve what’s going on with the skirt here? not even sure of the proper terminology to try to look up tutorials or patterns on my own.
The type of seaming on this dress is called “princess seams,” which is a term that denotes seams that run vertically over the fullest point of the bust. These are “armhole princess seams,” as they end at the armhole rather than the shoulder. Princess seams are typically a decorative way to get a bodice with curved shapes, as the seams accommodate the fullness of the bust while still allowing the rest of the torso to be fitted.
Breaking this down a bit further, the dress appears to have some sort of piping or trim inserted into the princess seams (note how the side seams are visible, but less thick and dark than the front seams), the skirt has a slight flare, and the princess seams open from the hip to reveal a light blue inset panel.
I would recommend getting a pattern that is relatively straight through the skirt, maybe with a small amount of flare, and creating the flare by adding the panels – these are basically triangles, and can be drafted yourself. You can use a pattern for a shorter dress and simply extend the bottom for length. Here are a few pattern options that would work well: 1 2 3 4 (Numbers 2 and 4 are the most basic and would be my top picks, personally.)
To draft the inset panels, make a mockup of the dress, and only sew it to the hip, where the opening begins. Try it on yourself or a dressform, and see how much it hangs open. I would recommend pinning in some fabric to hold the slits open slightly so you can see how it looks.
Measure how much you want the slits open at the bottom, and draw a triangle with that as the base measurement and the height as the length of the opening. If your base pattern is flared, make sure to draw the bottom of the triangle slightly curved to match the curve of the bottom of the dress – placing it inside the two pattern pieces and simply continuing the curve works for this.
For sewing, this is a good tutorial on how to attach the panel. (The term for this type of panel is a godet)
I hope that helps! Good luck :]