[the phantom]

That he was unable to control the thoughts of the Elves is due to their own innate abilities, and they ‘saw’ what he was attempting to do.

He wasn't unable. They just took their rings off before he had the chance to do it.

The interesting thing is that while Melkor used his powers to control others by the use of the language, could Sauron have refined this method by somehow using the rings?

The question still remains as to how Sauron could best Melkor into finally achieving the fact that he could control the users of the Rings, even the 3 of the elves.

Here's some answers from HoME X, Myths Transformed-

Sauron, however, inherited the 'corruption' of Arda, and only spent his (much more limited) power on the Rings; for it was the creatures of earth, in their minds and wills, that he desired to dominate.

And this-

Thus, as 'Morgoth', when Melkor was confronted by the existence of other inhabitants of Arda, with other wills and intelligences, he was enraged by the mere fact of their existence, and his only notion of dealing with them was by physical force, or the fear of it. His sole unltimate object was their destruction...Hence his endeavour always to break wills and subordinate them to or absorb them into his own will and being, before destroying their bodies. This was sheer nihilism...

And a bit later-

Sauron had never reached this stage of nihilistic madness. He did not object to the existence of the world, so long as he could do what he liked with it.

And here's some more-

Sauron indeed achieved even greater control over his Orcs than Morgoth had done...And he proved even more skilful than his Master also in the corruption of Men who were beyond the reach of the Wise, and in reducing them to a vassalage...

And finally-

Though of immensely smaller native power than his Master, he remained less corrupt, cooler and more capable of calculation... While Morgoth still stood, Sauron did not seek his own supremacy, but worked and schemed for another, desiring the triumph of Melkor, whom in the beginning he had adored. He thus was often able to achieve things, first conceived by Melkor, which his master did not or could not complete in the furious haste of his malice.... We may assume, then, that the idea of breeding the Orcs came from Melkor... The details of the accomplishment of this wickedness were, however, left mainly to the subtleties of Sauron.

Hope you enjoyed the quotes.