When I craft elfin names I think of them like pieces of music first—soft vowels, flowing consonants, a hint of age and forest. Elvish naming rules in high fantasy usually favor euphony above all: avoid abrupt stops and clumsy clusters, prefer liquids (l, r, n) and sibilants, and let vowels carry the melody. Roots often derive from nature (trees, stars, rivers) or abstract qualities (grace, shadow, memory), so names often feel like tiny descriptions. Look at 'The Lord of the Rings' and 'The Silmarillion' for examples: names that sound like words in a language rather than arbitrary strings.
Beyond sound, there are social rules. Elves commonly have multiple names—childhood names, public names, secret true names, and family or house names. Gender can influence suffixes or vowel choices (but not always rigidly), and patronymics or matronymics show lineage. Consider morphological patterns: pick a handful of prefixes, roots, and suffixes and reuse them to give cultural consistency. Dialects and ancient forms can explain odd spellings or archaic vowels.
Finally, think about script and pronunciation consistency. If your elves use diacritics, decide if they’re ornamental or phonemic. A simple guideline I use: every name should be pronounceable by the reader with a little practice and feel like it grew from the world you built—then it will stick with people long after they close the book.