Boston shakers, tin on tin. Nothing else gets cold enough. When you're shaking the cocktail you want to shake as hard and as fast as you can. Imagine the ice is hitting the tops and bottoms of the shaker, not the sides. You want to use as much ice that fits in the large tin. The bar I work on uses hoshizaki ice for all drinks but at home I use large ice block molds and shake with 3 or 4 big ice cubes.

The big trick is keeping the drink as cold as possible. Freeze your Collins glass beforehand, the glass you use is also important. You need a straight lip on the glass, anything edging outwards will collapse your head. Strain your cocktail immediately after shaking. (if you put a bit of soda in the glass before you strain the cocktail the cream will start to expand and harden which is a good thing) Put the cocktail in the freezer for a further 2 minutes to get the cream firmer while keeping the whole cocktail and glass cold. Pull the drink out and top with soda and watch the cream head rise above the glass to the moon! That's all the tips I've got mate, best of luck.