Be clear at the beginning of each lecture that you welcome questions at any time, and that there are no stupid questions.
Ask for questions after every slide and wait for at least a full 10 seconds – some students may take time to formulate their question.
You could even ask these to be submitted digitally (anonymously) during or after the lecture (so they could be summarised and answered at the start of the next lecture).
Constantly asking for questions results in much higher student engagement. It is also more inclusive as it encourages engagement from students who don’t usually participate in a lecture.