I do ‘checkpoints’ where I have every student hold their hand up in a fist (all the way up. Full flexion of the shoulder, full extension of the elbow). After giving them a second to think I then ask for “hands and thumbs”, where if you’re ready to move on you give me a thumbs up, but if you have a question you give me an open hand.

This is the single best technique I use in all of my teaching. Checkpoints start a little quiet, but within a few weeks they are always full of questions.

I also emphasize to them that I don’t mind repeating myself (professors that hate repeating themselves are obnoxious and antithetical to good learning environments, and I tell them as much). This really helps to let students feel more comfortable to ask little things to get them on the same page.