Supply users with a diary and ask them to keep a written record of their impressions, circumstances and activities related to the relevant aspects of their lives. The diary can be kept over a week or sometimes longer. Be careful not to ask leading questions that will distort the results you get: keep your questions open-ended and your language simple.
You could...
...give your users single-use cameras. These are an effective way to get users to record incidents, or environments. Photo diaries, which can be used in conjunction with a written diary or as a stand-alone piece of evidence, can be as simple as pictures of users' houses, or the contents of their fridge, but still provide valuable insights to users' habits.
...provide a pre-printed notebook or diary with prompts or questions. Make sure the visual design makes it easy to complete.
...talk through the diary in a follow-up interview. Alternatively, you could simply supply a stamped addressed envelope for the user to return the pack by post.
Resources
Optional: Diary or notebook and pen
Single-use cameras