Some are based on more subtle forms of behavior: Single males are more likely to be hit with online ads that move around. (discovermagazine.com)
The most common proposed model is a direct voucher, which has recently taken on more subtle forms such as tax credits and tax - sheltered education savings plans. (nassp.org)
Try this technique out in public (though maybe in more subtle forms) and see if people respond positively to your body language. (entrepreneur.com)