The approved technique is to open the vermouth bottle and let the fumes waft over the gin. Any more than that makes for an inferior martini. The alternative technique if having no frozen gin and having to use a shaker with ice is to rinse the shaker with vermouth, being careful to pour it all out prior to adding ice and the gin, then shake vigorously and pour into the martini glass from over your head (at least a 2 foot drop, to get enough oxygenation). As for the gin, I prefer Tanqueray Ten and if that is not available, Bombay Sapphire. Hate Gordons (but others love Gordons). Some of the dutch gins are also quite good, but also a lot different for true genevers.