One belief that emerged from the Reformation was the idea of justification by faith alone. This was articulated first by Martin Luther (and, previously, by a few other heretical groups in Church history.) Essentially what this meant for most Europeans was that one's salvation was not dependent on receiving the sacraments (and, not incidentally, that the sale of indulgences practiced by the Church was not scripturally justified.) The idea of justification by faith was based on the idea that Scripture was the ultimate source of God's word. Anything not justifiable by Scripture, Protestants argued, was the work of men, and irrelevant.
Another Protestant belief was the theory that the Church was a "community of believers" rather than a hierarchy one had to negotiate to receive God's grace. Protestants emphasized the notion of "callings," giving all occupations the same dignity as the priesthood in theory, and abandoned the idea of priestly celibacy, allowing priests to marry, as Luther himself did.
Many Protestants would embrace the idea of predestination, and some would argue that baptism, which symbolized the acceptance of God's grace by people, could only be valid if it involved a consensual decision. Therefore only adults should receive baptism.