The human mind often tends towards dissatisfaction. This is especially true in the world we live in today. Ryounsoke Koike described this tendency beautifully when he said:
'The problem here is that the mind has a habit of looking for stronger stimulation and can get out of control if we let it. Because negative thoughts have a much stronger impact on our brain than a mild, gentle sense of happiness, it's hard to prevent [negative thoughts from dominating]".
But you can train yourself and practise feeling grateful using meditations like this one. This will allow you to cultivate a positive frame of mind and feel more fulfilled in the moment.
Sit in a quiet space, and close your eyes if you wish to. First of all, think about why you're doing this. You're doing this to bring greater happiness not only to yourself but also to the world around you.
Begin by feeling the weight of your body on the chair and the ground under your feet.
Think about three things you are thankful for in your life. These can be anything: things, other people, situations. Think about each of these things in turn, and think about why you are grateful for them.
Then, cultivate this sense of happiness for others. Rejoice in the achievements and happiness of others. Start off with people you know well, and try to move on to people you don't know. Try to rejoice in their happiness and success.
Finish this meditation the way you started it - by reminding yourself of your intention to not just bring greater happiness to yourself, but to those around you and the rest of the world at large.
Source: A Monk's Guide to Happiness - Gelong Thubten