Will-power is a completely different thing, though there can be some overlap and some people who use metaphysical processes will be have a more "willpower weighted" approach than others but don't confuse the two. The more pure willpower you use the more limitation you place on what can be ultimately achieved.
There's been some great stories of accomplishment and survival utilising willpower alone. Joe Simpsons epic mountaineering survival "Touching The Void" springs to mind.
It isn't really all about some mystical or magical power, it's just another understanding of how things work, but it is different to pure self-accomplishment. LOA etc taps into a completely separate group of universal laws and your "will"
is involved to focus on and engage them, but not beyond that.
Some people are "better" at it than others as well, usually to the extent of being able to get out of the way of the process after initiating it.
Like anything else, there is no doubt that practise and experience play a role, if for no other reason than to produce a greater degree of confidence in the outcome and the understanding of the differences between willpower produced results and LOA type results.
I'll stop there wrenchands....I don't wanna cause ya an eyeache

If ya wanna get into it more perhaps we could head down a more "scientific" path to attempt an explanation of how and why this mumbo-jumbo works.