A Secular Humanist Declaration was issued in 1980 by The Council for Democratic and Secular Humanism (now the Council for Secular Humanism).

A few relevant excerpts and citations with highlights: 

Secular humanism is not a dogma or a creed. There are wide differences of opinion among secular humanists on many issues. Nevertheless, there is a loose consensus with respect to several propositions. We are apprehensive that modern civilization is threatened by forces antithetical to reason, democracy, and freedom. Many religious believers will no doubt share with us a belief in many secular humanist and democratic values, and we welcome their joining with us in the defense of these ideals.

On free inquiry:

Free inquiry entails recognition of civil liberties as integral to its pursuit, that is, a free press, freedom of communication, the right to organize opposition parties and to join voluntary associations, and freedom to cultivate and publish the fruits of scientific, philosophical, artistic, literary, moral and religious freedom. Free inquiry requires that we tolerate diversity of opinion and that we respect the right of individuals to express their beliefs, however unpopular they may be, without social or legal prohibition or fear of sanctions. Though we may tolerate contrasting points of view, this does not mean that they are immune to critical scrutiny. The guiding premise of those who believe in free inquiry is that truth is more likely to be discovered if the opportunity exists for the free exchange of opposing opinions; the process of interchange is frequently as important as the result. 

On separation of church and state:

Any effort to impose an exclusive conception of Truth, Piety, Virtue, or Justice upon the whole of society is a violation of free inquiry. Clerical authorities should not be permitted to legislate their own parochial views – whether moral, philosophical, political, educational, or social – for the rest of society. Nor should tax revenues be exacted for the benefit or support of sectarian religious institutions.

On freedom and human rights:

As democratic secularists, we consistently defend the ideal of freedom, not only freedom of conscience and belief from those ecclesiastical, political, and economic interests that seek to repress them, but genuine political liberty, democratic decision making based upon majority rule, and respect for minority rights and the rule of law.

We are for the defense of basic human rights, including the right to protect life, liberty, and the pursuit of happiness. In our view, a free society should also encourage some measure of economic freedom, subject only to such restrictions as are necessary in the public interest. This means that individuals and groups should be able to compete in the marketplace, organize free trade unions, and carry on their occupations and careers without undue interference by centralized political control. 

On ethics and moral education:

There is an influential philosophical tradition that maintains that ethics is an autonomous field of inquiry, that ethical judgments can be formulated independently of revealed religion, and that human beings can cultivate practical reason and wisdom and, by its application, achieve lives of virtue and excellence. 

We do not believe that any particular sect can claim important values as their exclusive property; hence it is the duty of public education to deal with these values. Accordingly, we support moral education in the schools that is designed to develop an appreciation for moral virtues, intelligence, and the building of character

On religious skepticism:

As secular humanists, we are generally skeptical about supernatural claims.

Symbolic and mythological interpretations of religion often serve as rationalizations for a sophisticated minority, leaving the bulk of mankind to flounder in theological confusion. We consider the universe to be a dynamic scene of natural forces that are most effectively understood by scientific inquiry

On reason:

We are committed to the use of the rational methods of inquiry, logic, and evidence in developing knowledge and testing claims to truth. Since human beings are prone to err, we are open to the modification of all principles, including those governing inquiry, believing that they may be in need of constant correction

On science and technology:

We believe the scientific method, though imperfect, is still the most reliable way of understanding the world.

On education:

The aims of education are many: the transmission of knowledge; training for occupations, careers, and democratic citizenship; and the encouragement of moral growth. Among its vital purposes should also be an attempt to develop the capacity for critical intelligence in both the individual and the community. 

In democratic societies television, radio, films, and mass publishing too often cater to the lowest common denominator and have become banal wastelands. There is a pressing need to elevate standards of taste and appreciation

In conclusion:

Secular humanism places trust in human intelligence rather than in divine guidance. Skeptical of theories of redemption, damnation, and reincarnation, secular humanists attempt to approach the human situation in realistic terms: human beings are responsible for their own destinies. We believe that it is possible to bring about a more humane world, one based upon the methods of reason and the principles of tolerance, compromise, and the negotiations of difference. We recognize the need for intellectual modesty and the willingness to revise beliefs in the light of criticism. 

Source: secularhumanism.org/a-secular-humanist-declaration