You don't denote 'quarter to (...)' or anything like that, you just use まえ (from 前) and すぎ (from 過ぎる)
4時前 A little before 4 o' clock.
AM / PM
use {午後|ごご} and {午前|ごぜん} for this. This is not really used in everyday conversation however. In conversation, people are more likely to specify with 朝 or 夜