Proselytizing religions do exactly that; tell others what to believe. Religions impose penalties on those who don’t accept the tenets of the belief system.Can anyone tell you what to believe? If the answer is no, then you have your answer. People are not all that different. Each has his or her own beliefs. Sometimes we are fortunate enough to run into those who share our own belief. We cannot tell one another what to believe; we can ask people to share what they do believe and how they came to that belief.Why not believe in all the gods and then just sort them into a hierarchy, thus making an ordered list of how the gods can meet your expectations?
No religion claims itself secondary in comparison to its competition. That would dismantle the authority of every religion ("Well, we're sort of right," said the Dalai Lama, "But you know, maybe those Christians are really right." Uh, not likely.) I’ve found it rare that believers will acknowledge an important component of religious faith: that the faith exaggerates the psychological concept of in-group/out-group bias.
If you are a Christian as opposed to a Moslem, your very self-identification tells me that you are announcing Christianity to be right, and Islam to be wrong-- unless you are purposely following a doctrine you believe is wrong (I suppose some people might do that, but whatever for?).