Thinking is cool.
Trying to stop thinking is a complete waste of time. You are alive, you have a brain and you think. Even meditation won't stop you thinking. But sometimes, we can have a tendency to overthink to the extent that we stop doing, complicate everything unnecessarily and perform worse than we could if our thinking was calmer and clearer. How do you cultivate a calm, clear-thinking mind? The answer is, by watching it.
Just observe it, and allow it total freedom. Let it run as fast and crazy as it wants. Don't try in any way to control it. Just be a witness, without judging it.
Not judging is crucial to observing the mind. If you think your thoughts are immoral or inappropriate in some way, you are judging them. Drop the judgement. Everything is fine. Let the thoughts pass through your mind. No harm is being done here. It's all just fiction, like watching an inner-movie.
After a while, you'll start to notice gaps arising between one thought and the next. It's like watching clouds in the sky passing, with gaps of blue in-between. These gaps are variously called No-mind, Zen, Tao, Yoga, Oneness or Open-awareness. They are rare moments of experience that are beautiful and, for all that they are short, deeply restful for the mind.
In these gaps, you have no fixed-mind or fixed ideas. Your mind is free just to be. But don't cling on to the gaps by saying, "I want more of this," because as soon as you do that, the interval is gone.
The gaps just happen - they can't be forced. So allow your mind to run free and don't judge it - just watch it.
And you don't have to be in the lotus position to do this. You can do this sitting in a chair in the garden, washing dishes at the kitchen sink or even when you've just gone into a daydream in a rowdy pub. But meditation, or just sitting in silence, can help us to learn to sit without judgement on ourselves and will therefore allow greater scope for you to experience the gaps, the restfulness and the freedom to move on with your day in mindful and creative ways that are a true expression of you.
For a guided Open Awareness meditation or other guided mindfulness and calm-abiding meditations, check out Malcolm Huxter at http://www.buddhanet.net/audio-meditation.htm
Keep smiling and may you be well and happy.