Front foot planted. Using the momentum of the hook to pivot about 90 degrees with front foot still planted. Doing the most rotation at the impact of the punch.
Loose shoulders, not opening your guard too much and let you upper body to do the job (the power from below goes for the power punch after it). Compact, quick, accurate and stable
Here's my interpretation of what was taught to me To start, I'd have a day of just doing left hooks on the pad. Like below. http://i.imgbox.com/d793cDWT.gif Keep you hand low and not at striking level, and have your trainer mimic the gif. This will force you to rely on your hips to initiate the punch, which is absolutely pivotal. I don't know your skill level so don't take this the wrong way. I think the development of a great, fluid, left hook relies 100% on your ability to throw a check hook. Check out Shannon Briggs check hook, after a step back http://i.imgbox.com/s93UuUD8.gif And terrence crawfords while turning his opp http://i.imgbox.com/In28RYdk.gif To get the most out of your check hook you must **** back your arm first before throwing it out. This will give it whip, like Demetrius Andrade below http://i.imgbox.com/ogd8YzzE.gif **** back your arm until the tip of your elbow is pointing behind your back. then whip it out. this will spring load your check hook and give it a lot more pop.....
Hmm I'd tend to disagree about the bolded. Unless you're talking about a combo check-hook/jab? Still need to shut the door with your hips, or you'll get no whip on the punch. It's easier to throw it as just an arm punch if you're backing out (see the briggs clip above).
It's not supposed to be a power punch. It's a punch to "check" your opponent coming in. Lol hence the name. It is the reason they teach you not to just walk in because any decent fighter will catch you with it. Speed is more important than actually throwing power behind it. Without speed that defeats the entire purpose of throwing it.
Slightly tricky this one... To me it depends on the situation however the punch in itself i prefer the short chop. A go-through punch is ok if your feet and hips are properly placed. (Pacman vs Hatton inside drophook) Using this punch as an add to your jabbing game is cool. As a basic i start out slightly off center (towards the outside of my front leg) with my front shoulder somewhat retracted then i let the hook go forward at an arc (initially as if i´m jabbing past my opponents head) outside then it closes in and i turn my front shoulder into the punch (actually i´d prefer to say that i pull with my rear shoulder simultaniously). In the extensive addable "options"-list i´d highlight as no 1: the pullback for adding power, no 2: the forward/inward fullbody tip or drop. no 3: the option to step into the punch and rotate out. Just my 2 cents on this... Have a good one