Shiva Abhishekam Procedure :

Items required :

Abhisheka liquids : Water mixed with Gangajal, unboiled milk, Sugarcane juice and/or Coconut water.
Punchamrit which is mix of unboiled milk , honey , sugar, ghee and curd.

Water mixed with Ganges water in a achamani pot with Kusha grass for sprinkling and a spoon

Dhoop , Incense sticks, Camphor, Ghee lamp

Sandal paste , Aromatic oil .

Rice grains

Offerings – Sweets, Clothes, Flowers, Fruits, Betel nut, Bael Patra, Paan , Coconut

Place Lingam so that Yoni faces North and you are facing the West face of the Lingam and looking towards East. You need to sit on an Asan of wool/ Kusha. It is best to do Pooja of Lord Shiva while wearing Rudraksha on your body as it is His favorite bead.

Sprinkle water over yourself and all items of Puja chanting.

Om Apavitrah Pavitro Va Sarva Vastan Gatopi Va
Yah Smaret Pundari Kaksham Sa Bahya Bhyantarah Shuchi

Translation:
May all things unholy become holy, may all lower tendencies depart, just as soon as we transcend may within and without be purified!
Then Chant:

"Om Gurubhyo Namaha
Om Ganeshaya Namaha
Om Kula Devatabhyo Namaha
Om Ishta Devatabhyo Namaha
Om Mata Pitribhyam Namaha"
Translation:
I bow to guru, I bow to Ganesha, I bow to the family deity, I bow to my personal deity, I bow to my parents
Place water on right hand with spoon of Achamani and sip after each of these 3 mantras
"Om Keshavaya Namaha
Om Narayana Namaha
Om Madhavaya Namaha"
Place water on right hand and pour on ground:
"Om Govindaya Namaha"
Do three short rounds of pranayama breaths.
"Om Pranavasya Parabrahma Rishihi Paramatma Devata
Daivi Gayatri Chandaha
Pranayamae Viniyogaha"
Bathe lingam with water and then all Abhisheka liquids one by one. The bathe Him with Punchamrit and again with water. All this while chant “Om Namah Shivaye”. Wipe Him and place Him on Pedestal.
Now chant Sadyojaat mantra
Om Sadyojaatam Prapadyaami Sadyojataajava Namo Namaha
Bhave Bhavenaati Bhave Bhavasvamaam Bhavodbhavay Namaha
Offer Sandal Paste making a Tripunda on His Western Face with Vamdev mantra

Om Vamdevaya Namah, Jyeshthaay Namah , Shreshthay Namah , Rudraay Namah , Kaalay Namah ,Kala Vikarannaay Namah, Bal Vikaranaay Namah, Balaay Namah Bala Pramathanaay Namah, Sarva Bhoot Damanaay Namah, Manomanaay Namah.
Offer dhoop and incense to Him with mantra below

"Om Aghorebhyo Ghorebhyo Ghor Ghor Tarebhayaha
Sarvebhya Sarva Sharvvebhyo Namaste Astu Rudra Roopebhyaha"
Offer flowers with mantra below
"Om Tatpurushaaya Vidmahe Mahadevaay Dheemahi
Tanno Rudraha Prachodayaat"

Chant Eeeshan mantra

Om Eeshaanah Sarvavidyaanam Eeshwar Sarvabhootaanaam
Brahmaadipati Brahmanaadhipati Brahma Shivome Astu Sadaa Shivom
(Invocation) Avahanam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha
(Seat) Asanam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Cloth) Vastram Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Sandalwood or scent) Chandanam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Rice) Akshatan Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Flower) Pushpam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Dhoop) Dhupam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Ghee lamp) Deepam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Water drink) Achamaniyam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Fruit) Naivedyam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Water Drink) Achamaniyam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Betel nut - Paan) Tambulam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

(Coconut) Shri Phalam Samarpayami Sri Shiva Maha Devaya Charana Kamalebhyo Namaha

Burn Camphor and offer to Him
Karpura Shivam Karuna Vataram Samsara Saram Bhujagendraharam
Sada Vasantam Hridaya Ravinde Bhavam Bhavani Sahitam Namami
Chant Gayatri mantra 3 times

Om Bhur Bhuvah Swaha
Om Tat Savitur Varenyum Bhargo Devasya Dhimahi Dhiyo Yonaha Prachodayat
Chant Surya mantra 3 times

Om Bhu Om Bhuvaha Om Swaha Om Maha Om Janaha Om Tapaha Om Satyam

Repeat and touch each after each mantra, right eye, left eye, forehead

Om Apo Jyothi
Raso Amtritam
Brahma Bhu Bhuvaha Swarom
Chant Mahamrityunjaya mantra 108 times with Rudraksha mala.
Om Haum Joom Sah ,Om Bhur Bhuvaha Swaha
Om Triambakam Yajamahey,Sungandhim Pushti Vardanam
Urvar Ukamiva Bandhanan,Mrityor Muksheeya Mamritat
Om Swaha Bhuvaha Bhu Om Sah Joom Haum Om

Bow or supplicate, then chant this last prayer :
Om Purnamada purnamidam purnath purnamudyachite
Purnasya purnamadaya purna mevaya shishyate
Om Shanti Shanti Shanti