Your iPhone camera has a "quick mode" just for shooting a Contact photo. Get in the habit of shooting a photo when you meet someone and add them to your Contacts. Once you have their contact infomation entered:
- Tap Add Photo/Take Photo.
- Shoot the subject from about 6 ft. away. They won't look distorted by the lens like they do when shot close up.
- Hold the green camera button and release it to take the image.
- Drag the image up or down to move or scale by pinching out. Make sure the person fills the square frame.
- Tap Set Photo.
- While viewing the photo tap the leftmost button on the bottom of the image. (The photo with the arrow coming out of it.)
- Choose Assign to Contact.
- Pick the person from your Contacts lists.