When I read and I come to a really big word that I don't know, I do use syllabication rules. I use them without realizing that's what I'm doing. I don't remember being explicitly taught the rules of syllabication; I think I just learned them from repeated visual exposure to lots and lots of words.
However, when I was getting my credential, I made sure to learn all five syllabication rules that were in my textbook, for fear that if I didn't know the exact wording in the textbook - as opposed to using common sense - I would be deemed incompetent in reading instruction.
1)When 2 consonants come between 2 vowels, like coffee, divide the syllables between the consonants (cof-fee).
2)When a word has more than 2 consonants together - like lobster - divide the syllables to keep the blend together (st in lob-ster).
3)When a word has 1 consonant between 2 vowels - like glacier - divide the syllables after the first vowel (gla-cier).
4)If you try the 3rd rule, but it doesn't work - like method doesn't make a recognizable word when you read it aloud as me-thod - divide the syllables after the consonant (or blend) that comes between the vowels (meth-od). Other words that fit this category are dozen (doz-en, not do-zen), courage (cour-age, not cou-rage), and echo (ech-o, not e-cho).
5)When a word has 2 vowels together that don't stand for a diphthong (example: "oi" in loin) or a long vowel sound, divide the syllables between the vowels. Take the word "client." The "ie" doesn't say "i," so you divide the syllables between i and e (cli-ent). Other words in this group: poem, lion, and duo.