While fixing a Muhurtha ....avoid following combinations and malefic yogas
1) Spoorjitham. - The Sun in kendra causes this yoga and the result is the destruction of the family.
2) Spuritham. - Mars occupying a kendrs generates this evil yoga and generally proves fatal to the Guru (preceptor) as well as the boy.
3) Rudhitham. - Saturn occupying a kendra produces this evil combination resulting in incurable diseases.
4) Rundhram. - Rahu in a kendra gives rise to this malefic yoga. It proves fatal to the mother.
5) Ugram. - This arises by Ketu's disposition in a kendra. It adversely affects health and education
6) The Moon should always be avoided in Lagna. But, however, if Cancer is the ascendant and the Moon and Jupiter are in conjunction and malefics are in 3, 6 and 11, the evil attached to the situation of the Moon in
Lagna becomes neutralised.
7) The Moon must not occupy the 6th, 8lth, or 12th house.
8) Malefics should not be posited in quadrants.
9) The ceremony should take place before noon.
10) The 8th house from the Lagna must be unoccupied.
Courtesy : Muhurtha (Electional Astrology) by B.V. Raman