Now it came to pass that while the Valar rested from their labors, and watched the growth and unfolding of the things that they had devised and begun, Manwë ordained a great feast; and the Valar and all their host came at his bidding...One unusual wedding website quotes extensively from a "Morgoth's Ring" chapter: "Laws and Customs among the Eldar"
And it is sung that in that feast of the Spring of Arda, Tulkas espoused Nessa the sister of Oromë, and she danced before the Valar upon the green grass of [the island] Almaren.
Then Tulkas slept, being weary and content.
"At the end of the feast the betrothed stood forth, and the mother of the bride and the father of the bridegroom joined the hands of the pair and blessed them. For this blessing there was a solemn form, but no mortal has heard it; though the Eldar say that Varda was named in witness by the mother and Manwë by the father; and moreover that the name of Eru was spoken (as was seldom done at any other time). The betrothed then received back one from the other their silver rings (and treasured them); but they gave in exchange slender rings of gold, which were worn upon the index of the right hand.
Also, among the Noldor, it was a custom that the bride's mother should give to the bridegroom a jewel upon a chain or collar; and the bridegroom's father should give a like gift to the bride. These gifts were sometimes given before the feast. "
I extract these elements from the entire quoted text:
Courtship♥ usually with familial approval
♥ sometimes since childhood
♥ no pre-marital conjugation
Handfasting♥ in early adulthood, soon after age 50
♥ the father physically giving the daughter's hand to the groom
♥ the families announce betrothal.
♥ the two exchange silver rings
♥ handfasting lasts one year at least, often much longer.
The return of the rings signals revocation of intent to wed. Recall "one year" in age of the Trees is about 9.5 sun-years, so that is a nice long hand-fasting. In modern parlance, the "engagement" is similar: a time where the couple and their families learn to deal with each other and a large project of arranging the wedding celebration itself.
Marriage Ceremony♥ brides mother and grooms father join the couple's hands.
♥ those parents bless them, solemnly invoking Manwë, Varda and Ilúvatar
♥ the silver rings are returned to one another
♥ gold rings are exchanged
'To Juli my beloved, my life and my love'
The Wedding Feast♥ occurs before or around the ceremony
♥ the king and/or father usually presides
♥ jewel and jewelry gifts are given to the couple
♥ food and music and dancing and vast attendance
♥ then sleeping happens and life goes on.
Now, to locate some elvish "solemn form blessings" to make a ceremony.