How do I not smile at all?

To completely avoid smiling, you need to consciously control the muscles in your face. Here's a technique based on the provided reference:

Purse your lips: Actively press your lips together. This physical action makes it difficult for a smile to form naturally.

Techniques to Suppress a Smile

Here's a breakdown of effective strategies:

Physical Control:
- Clench your jaw: Tightening your jaw muscles counteracts the upward movement associated with smiling.
- Press lips together: The reference clearly suggests pursing or pressing your lips together. This restricts the muscles needed for smiling.
Mental Focus: Thinking about something sad or serious can naturally inhibit smiling. However, since the question is just 'how do I not smile at all', I haven't included this in the answer.

Smiling is often an involuntary reaction to happiness, amusement, or even nervousness. Consciously suppressing it requires effort and concentration.