Mars occupying the 1st or 4rth or 7th or 8th or 12th house of the birth chart and this Mars is not of its favorite signs-Aries or Scorpio or Capricorn then the birth chart has Manglik dosha. Such a birth chart has problems in married life and are advised to marry after 28years of age and preferably with a partner who also has Manglik dosha. A person having Manglik dosha as a precaution is advised to look the horoscope of the partner before finalizing and worship Lord Ganesha every Tuesday and as much as possible.
A girl having manglik dosha is advised peepal vivah. and Moonga (Coral) is recommended ratti as per degrees of mangal in chart.
For early marriage Katyayni yantra can be other great help.