Manglik Dosha should be considered by looking at the placement of the planet Mars (Also known as Mangal, Kuj, Bhowma) from the ascendent (Lagna) Moon and Venus.
From the lagna placement of the Mars is considered to be stronger than the moon and venus.
the placements are 1, 2, 4, 5, 7, 8, 12
for male 2, 7, and 8
for female 4, 8 and 12th position of Mars will give bad results.
according to some, we should not consider the negation.
remedy: In Karnataka Visit the Kukke Subramanya Temple and perform the pooja to Lord Subramanya (Murugar).
Kujavath ketu, shanivath rahu means Ketu gives the same effect of Mars and Rahu gives the same effect of Saturn. propitation of these two will result in propitating Mars and Ketu.
check the link for more info.
http://www.panditjiusa.com/Mangal_Dosh.htm