zig zag over a piece of crochet thread and then just pull to gather. Since the crochet thread is thicker you don’t have to worry about it breaking and you have tons of control so you can distribute the gathers much more evenly without worrying that everything will come undone.
First grab yourself some crochet thread. Set your sewing machine to a nice big zig zag I usually do 4 for the length and 5 for the width. What you want is a nice big zig zag that will go over the crochet thread without you having to be too careful.
Then lay the thread where you want the gathers and start to sew making sure not to have the needle touch the crochet thread and making sure you back stitch at the beginning and end. When you reach the end of what you need to gather cut the crochet thread leaving a long tail.
Then pull to gather. Tie or tack down the ends with a pin and distribute the gathers as desired. And that’s how to gather the easy way!