Men vary in physical strength. This can be caused by many different factors, putting much effort into physical fitness, being genetically tall and muscular etc. It is usually a combination of different thing, but can still be quantifiable.
Elves may also vary in physical strength, but they also appear to vary in that other strength which humans call magic. What causes some elves to be vastly more powerful than others? Elrond and Galadriel seem to have immense power (especially Galadriel as portrayed in the movies). This could be attributed to the three rings, but there seem to be different levels of power even amongst those who did not carry rings. For example Glorfindel seems capable of feats of the kind that were never demonstrated by Legolas.
So, what is it that causes some Elves to have more 'magical' power than others? Is it something genetic or something learnt? A combination of both?
I appreciate that 'magic' and 'power' are never really described/quantified within books published within Tolkien's lifetime, but are there any sources at all this?
I have read Can the Elves do magic? but it doesn't fully answer my questions, merely reinforces that Elves do have different levels of power and this is caused by unspecified things that are analogous to those that vary physical power. My question is, what are these unspecified things?