Refold hems at side seams, this can be done with a finger press and securing with a pin.
Pin hem as needed, match center front seam to center front seam.
Stitch hem 1/8'' from edge of hem. Make sure to back tack at start (and end). Beginner tip- stitch bodice back first for practice.
End at side seam, make sure to back tack:
It isn't uncommon for your stitching to be a little rippled or puckered. This can be pressed out with an iron. If it is severe, it may be a needle/machine issue. You can troubleshoot this problem here: Sewing Machine - Nuances You Should Know About
Press seam flat with iron. A taylors clapper can help lock fibers in to place (I use a piece of scrap wood from a house project). Keep it placed on the them until it cools.
There you have it, a nice smooth hem!
Refold hem at side seam, finger pressing works fine.
Pin into place at side seam:
Start stitching at side seam to hide back tack under arm, stitch 1/8'' from edge of hem. I usually turn my garment right side out for this step as pictured below:
Finish stitch at under arm seam, back tack, snip loose threads, and give a final press.