Here at ASHW we don't call Mindfulness a meditation. This is to make sure you see mindfulness as something to do when convenient, when alone. Whether walking or working in the home, if you are doing something fairly automatic which doesn't need too much concentration, then you can practice mindfulness. You don't need to set aside special times for mindfulness, you just do it.
So, what is it that one just does? Using the skills acquired from insight meditation, just concentrate on what you are doing, whether it be walking, washing up or making the bed. Personally, I prefer to practice mindfulness when walking. You don't need to say anything. If walking, don't go left foot here, right foot goes here etc., just keep quiet and be open to all that arrives in the way of sights, sounds and smells. When thoughts arise just notice them and let them go, much as you do when practicing insight meditation.
How is Mindfulness different from Insight Meditation? With Insight Meditation, you pay enough attention to arising thoughts to help you understand them and their relationship to emotions. With Mindfulness the attention is on the lack of thought and becoming used to a mind experiencing the world without commentary. In other words, you become familiar with the idea that it is not necessary for your internal chatterbox of a voice to be continuously talking.
With a little practice, you will find immense benefit from practicing Mindfulness. The first of these benefits is calmness. Another benefit is seeing and hearing the world more clearly. You will see things you never noticed before. Nothing amazing — unless you have strange neighbours — but the items of your neighbourhood will just be more noticeable.
When should you practice? Whenever you do not have a pressing need to think about problems or concentrate on what you are doing. For many people this can be more than half the day.
Try it! I promise you, it is a sensational practise.