If we have to choose between angels who encourage us to worship the one true God and angels (well, "angels") who encourage us to worship themselves, is there any rational being that can say we should obey the latter? One sign of angelic powers working in favor of the truth is that they direct us to the one true God.
But what of the miracles worked by the other angels? The standard is the same--anything which turns us to the true God is of God, anything which turns us to false gods is demonic in origin.
If we want proof, we need only look at how the miracles surrounding the Ark of the Covenant in the Old Testament highlight the glory and power and worth of God.