Consonant-verb regularities

I wonder if you all might indulge a neophyte question. Now, some
languages, such as Russian, have lots of consonant combinations.
Others, such as Hawaiian, use vowels more heavily. Some seem to
insist that every syllable be a consonant followed by a vowel. I
sense
a number of vague patterns here. Are there any regularities in the
relative use of vowels and consonants? Do most languages have some
sort of ironclad rule regarding vowel-consonant relationships? For
example, Japanese, I believe, seems to follow the rule that each
syllable consists of one consonant followed by one vowel -- but there
are a few exceptions, I believe. Do such exceptions tend to follow a
rule?

I suppose that the thrust of my question is, are vowel-consonant
relationships fundamental to a language, and therefore subject to
strict rules, or are they more a matter of local fashion, with lots
of random exceptions?

Thank you for your indulgence.

Chris Crawford