i predicte that even though someone has already posted the basics to doing 540s and 360s everyone else will just post the exact same thing even if they know someone else already has.....like me,
spread your legs apart, shoulder width or a tad more, come to the lip with confidence, make sure you start after you reached the end.... twist your arms and look over your shoulder, drop your arms, keep looking till you spot your landing then stretch out for obsorbing the landing, and make sure its not pencil or i'll throw shit at you!