Bob, I like your thinking. Might just have to borrow that one day!
If you are going to walk in, dress neat. Plain pants, a shirt, I'd suggest a tie too. Don't need a formal suit, don't need your pseudo-uniform from your CPL training. Jeans and a t-shirt is a no-no, same with shorts singlet and thongs (however, I know of one place up north where that's probably a better idea!).
Be polite to the front desk staff; you might actually be speaking to the CP, owner, their wife, someone senior etc.
A simple introduction and statement of why you have dropped in. Don't just give them your CV, ask if they will take it and pass it on and mention that if the CP would like to have a chat then you are more than willing to come back another time if they are too busy at the moment. CPs are busy and can't always chat when randoms drop in.
You are not entitled to a job, you have to earn it. There's going to be a lot of rejection on the way.
Don't BS anyone, work hard, be polite and friendly. Once you get that first job work your arse off. Future jobs up the ladder will be easier to get.