How do you transition into insight meditation?

[Mikeler]

I've been doing Shamatha (calm abiding, mindfulness of breath) meditation for some time now and I'm just wondering, at which point do I transition into vipassana or insight meditation?

What should I be doing differently and what should I expect?

So far I've just been developing concentration by focusing on the breath, but I'm wondering where the "wisdom" comes in.

Thanks.

[Dharmic Tui]

You can bring vipassana in at any time, in fact I imagine you already have been unconsciously if you have been noting and addressing thoughts. It's just that it is often easier if you have managed to calm yourself first.

[Mpgkona]

Vipassana is not really something that you necessarily do, rather it's a byproduct of meditation. Vipassana simply means insight, and through meditation insight is hopefully achieved. Insight, however, is not something you should be seeking through meditation. It will occur naturally through right technique and especially right effort. Nevertheless, I believe what you are asking is when to use techniques that may lead to insight. Whatever your technique is, whether it is through observing sensations, noting thoughts or feelings, etc. I would recommend starting this when you have achieved calmness or right concentration.

[Mikeler]

The only practice I use is mindfulness of breath (specifically abdomen rising and falling).

When my natural breathing gets too shallow to the point where I can't notice it, I try to detect any sensations in the body.

[Billymac629]

There are some really good answers here.   I will just add that if you keep using mindfulness of breathing, then just keep following the steps in Anapanasati (mindfulness of breathing).  There are 16 steps..  I believe everything after the 4th step is dealing with aspects of insight (vipassana).
It should be noted that the Buddha never really separated concentration and insight in practice.... 

[Matthew]

Billymac nailed it:

...
I will just add that if you keep using mindfulness of breathing, then just keep following the steps in Anapanasati (mindfulness of breathing).  There are 16 steps..  I believe everything after the 4th step is dealing with aspects of insight (vipassana).
It should be noted that the Buddha never really separated concentration and insight in practice....