You will find no finer or deeper teaching on Loving-Kindness than that of Ven. Bhante Vimalaramsi. I hope this short excerpt from a talk he gave on bringing loving-kindness to daily life will send you to his website to read the whole article. (Link below)

Ven.Bhante Vimalaramsi

What we need to learn how to do is carry that open heart with us with all the different activities we do during the day. Open up and… well, let’s put it this way. When you’re doing your sitting practice, you send Loving-Kindness to yourself and you send Loving-Kindness to your spiritual friend, and that’s all.

But with your daily activities, the other times, you can send Loving-Kindness to anybody. You can send it to individual people, you can send it to groups of people, you can send it to all beings, it’s up to you.

But the thing that you want to try to do is start making keys for yourself. A key like: when you’re brushing your teeth, that that’s your time to send Loving-Kindness. When you’re walking from your house to your car, try to use that as a key, for that’s the time to open up your heart and send Loving-Kindness.

Now you’re going to forget sometimes, just like you do here, and that’s OK. There’s no problem with that. But when you see your mind is wandering, then you want to begin again. And that should be the name of this practice: “Do It Again”, or “Play It Again”, is that the…? [laughter] When you’re walking from your car to wherever you have to go, what are you doing with your mind? Your mind is just kind of ho-humming around, getting caught in all kinds of unwholesome mental states, or it’s just kind of flying around thinking about this or that. So you use that, getting out of your car, or getting into your car, as your key to practice your Loving-Kindness. Open up your heart and, and if there’s someone that you know that is suffering, send them some kind thoughts. Put them in your heart, radiate that Loving-Kindness to them.

The more times you focus on having an open heart, the more easily the practice progresses. And this is because, when you have an open heart, and you’re radiating that Loving-Kindness, you’ll notice it very quickly when it closes, when you get caught by thoughts and feelings and all kinds of whatever the circus is that’s running in town at that day. So gently let go of those thoughts, let go of those feelings, relax. Wish somebody happiness.