It is assumed that every planet before entering any sign may start giving results of that sign according to following ways.
Sun is starting giving results before 5 days of his sign change.
Moon is starting giving results of next sign before 1.25 hours of his transit to a sign.
Mars is starting giving results of next sign before 8 days of his transit to a sign.
Mercury is starting giving results of next sign before 7 days of his transit over a sign.
Venus is starting giving results of next sign before 7 days of his transit.
Jupiter is starting giving results of next sign before 2 months of his transit.
Saturn is starting giving results of next sign before 6 month of his transit.
Rahu and Ketu is starting giving results of next sign before 3 month of transit.
Apart from this
It is assumed Sun and Mars gives results with full power in 1st drekkana (0 to 10°) of Sign.
Jupiter and Venus gives results with full strength in 2nd drekkana (10 to 20°) of sign.
Moon and Saturn gives results with full strength in 3rd drekkana (20 to 30°).
Area Of Body part affected due to transit of Planet
Sun – Head part of body
Moon – Heart and neck part of body
Mars – Abdominal or waist part
Mercury – Hand and legs
Jupiter – Waist and thighs
Venus – Sexual and hidden organs of body
Saturn – knees part of body
If any planet in unfavourable transit then they may effect above part of body according to their Tridosh (kapha, Pitth, Vata ) significant.