Some machine brands have several pintuck feet from which to choose. My Berninas have four different pintuck feet: 3 groove, 5 groove, 7 groove and 9 groove. The grooves serve a couple of purposes. After making one pintuck, that pintuck can be laid in one of the grooves of the foot, while stitching another, making perfectly spaced tucks. Or, cording can be inserted under the grooves to make a corded pintuck. Here you can see the feet, and the difference in them.
The 9 groove would be suitable for a very lightweight fabric, as opposed to the 3 groove, which is more appropriate for a heavy material.
With these feet, choose a twin needle--2.0 (width between the needles) for a 9 groove foot, and 4.0 for the 3 groove foot, and of course, numbers in between for the others. Thread the twin needles, increase the top tension and--sew. That's all there is to it! The tucks will form on the top of the fabric with straight stitches, while the bobbin does a zig-zag, pulling the fabric together on the back, forming the pintucks.
Here's the front of my tucked fabric, and the back, showing how the fabric has been pulled together.
The bib is finished, and neckband is on. More tomorrow.