Most important Abhishek to Lord Shiva is RudraAbhishek.

Anyone can perform basic snan or abhishekam to Lord Shiva at home. We should even offer pure water or milk to Shiva at home. The Meaning of Abhishek is Snan or Holy Bath to Lord. There are many types of Abhishek. Most important Abhishek to Lord Shiva is RudraAbhishek. Rudrabhishek is tough and only priest can perform it. ‪Any devotee who wants to perform basic abhishek daily in prayer room of house can perform one with Holy water or Panchamrit Abhishekam. The favourite leaves of Shiva are bilva patra. We should offer few bilva leaves and white flowers while worshipping shivalingam.

1 – Holy water Abhishek – One can please Shiva by performing Abhishek with Holy water from any holy river like Ganga. One can please lord shiva easily if shiva snan is done with Holy water. Drinking One drop of water from Shiva snan helps attain freedom from all sins. One will get enternal blessing of Shiva.
2 – Panchamrit snan ~ The meaning of Panchamrit is 5 nectar combination to please Lord Shiva. The Holy bath to lord with 5 nectar is Known as Panchamrit abhishek. The Five nectar substances are Sugar, Curd, Honey, milk and Ghee.

Start with Hymns praising Lord Shiva or the mantra ‘Om Namah Shivaya’ to create a mood for worship. Then, then sit in front of the Lingam and blow conch. First it is the Panchamrita abhisheka. While pouring the liquid, Om Namah Shivaya is uttered. After the Panchamrita Abhisheka, the Lingam is cleaned with Ganga jal. After this the lingam is smeared with sandalwood paste and is decorated with flowers. Water and sandalwood paste is used to keep the lingam cool, as Poison during Samudra Manthan Had burnt Shivas throat. In Shiva temples, cooling liquid constantly drops from pot hung above the Lingam. It's called Dhara Patra. Offer sweets, coconut and fruits to the Lord after Abhishek. Camphor and incense are lit and Aarti is sung. White ash (vibhuti) is rubbed on the forehead. Finally Fruits, sweets and coconut are distributed as ‘prasadam.

Only cold water and bel is offered to Shivalingam. One should never offer turmeric, vermilion (kumkum) or white consecrated rice (akshata). Since Shiva is the deity of dissolution, vermilion and turmeric are not used in His worship. Holy ash (bhasma) on the contrary symbolises dissolution and is thus used. One should not commence the ritualistic worship of Shivalingam without application of holy ash (bhasma). Worship of Lord Shiva removes distress and poverty, grants learning and wealth, bestows all desires. Vedas and Puranas declare that worshiping Shiva in the linga form helps one gain highest merit in his life and in the future lifetimes. Accumulated sins of many lifetimes get washed away by performing Abhishek with sincere devotion and prayers to the lord, it's mentioned in Shiva Maha Purana. Also Worshipping Shivalingam helps one attain Moksha (Salvation) ,one will be free from the cycle of birth and death by worshiping Shivalingam. Shiva Purana states that nothing is as holy as Shiva puja.
Om Namah Shivaya ~ Jai Shri Mahakal !