Almagro vs Wawrinka 2012 Aus Open
http://www.youtube.com/watch?v=oXCKvawrmuY
Even to the beginners, the optimal technique makes learning much easier and productive.
I recommend,
Grip-E bh (not 'steaknife' nor 'mountainbike', just in between)
Stance-closed and keep the hips and shoulder sideway before and right up to contact
Weigh transfer-back to front foot
Swing path-Almagro, Gaudio, Kuerten (prepare high with elbow up shoulder level and finish high and around the body not start low finish high; for high balls racquet head could be above hand at contact)
Wrist- firmly neutral at contact (neither extended nor flexed) and supinate forearm and extend wrist for finish; this firm but well controlled wrist work with the optimal swing path makes dealing with high balls easier and adds topspin; do not keep it locked extended but do practice locked at neutral
There is absolutely no need for more extreme grip because the wrist control can achieve that. E bh grip with neutral wrist will necessitate hitting out in front. And at contact the racquet and arm angle is way more than 90. more like 120 or so.