Shani is one of the Navagrahas which are the nine primary celestial beings in Hindu astrology. Shani is embodied in the planet Saturn. Shani is the Lord of Saturday; the word Shani also denotes the seventh day or Saturday in many Indian languages.
Favourite Color
Blue, Black

Favorite Day
Saturday

Favorite God / Deity
Lord Hanuman

Reducing or Nullifying the malefic influence of Shani
The ill effects of Saturn can be minimized and the good effects can be magnified by performing any or all of the following tasks. 

1.Donating a piece of black cloth, silk cloth, a cow, a buffalo, a mare, black grams and Black Til (Sesamum Seeds) on Saturday will amply influence Saturn to bestow benefits on devotees and to keep away from adverse effects, because these are the colours and objects dear to Him.
2.Donating Mustard oil on any Saturday will appease Saturn Planet.
3.Wearing blue sapphire on any Saturday on the middle finger after testing its suitability is considered to bring favours of Saturn. Once worn on any Saturday, the ring should be worn for a long time.
4.Offering Mustard oil and Black Flowers in Hawan (Fire Sacrifice) will also add the favour of Saturn. 

Lord Shani In Astrology 
In Sanskrit Shani comes from SANISCHARA, which means, slow mover. From Shani we get the word shun which means to ignore, or lose awareness of something. Thus, Saturn represents a loss of awareness, or ignorance. This loss of awareness can also mean the diminishing awareness of the material world of manifestation. 
Here Saturn indicates the ascetic, rich with inner spirituality, and lost to this material plane of existence. Saturn is a malefic graha. He rules over the two sidereal signs of Capricorn and Aquarius. He is exalted in Libra, and fallen in the opposite sign of Aries. 
Saturn is a karaka, or indicator, of longevity, misery,sorrow, old age and death, discipline, restriction, responsibility, delays, ambition,leadership and authority, humility, integrity, wisdom born of experience.Saturn also indicates asceticism,denial, non-attachment, spirituality, hard work, organization, reality and time itself. Saturn's most powerful place in the chart is in the 7th House and the Kendra's,or Angles. He is a particularly beneficial planet for Taurus and Libra Ascendants.
Saturn's nature is Vata, or Airy. His gem is Blue Sapphire and all black stones and his metal is Lead. 
Saturn's direction is west and his day is Saturday. He reaches full maturity at age 36. 
In Vedic myth Saturn is the son of the Sun,born to his shadow wife, Chaya. Saturn is lame because one of the Sun's firstwife Sanjana's children angy with him,struck him in the foot. ThusSaturn walks with a limp, which accounts why he is the slowest of the Grahas.
The graha SANISCHARA (Saturn), also known as Manda, is generally known to affect one adversely on occasions when he occupies certain positions in one's horoscope like Saade Sati (7 1/2 years) Ashtama Shani (Saturn in 8th house - 2 1/2 years) etc. 
He is the Lord of Makaram and Kumbam. He is the slowest moving planet taking 2 1/2 years in each Rasi, completing one cycle every 30 years. A prayer to this Devata, especially on Saturdays, is said to mitigate the hardships one will have to face during these periods. Sanischara bestows all benefits to the devotees who pray sincerely to him.