I've given you three stars as how a man makes his martini is a very personal thing; however, that for me is not the way you make a gin martini.
Winston Churchill: "The way to make the perfect Martini is to pour an ice cold gin, drop an olive in it and bow in the direction of France". This is almost definitely a misquote.
Winston is correct about the vermouth though, if he may be exaggerating slightly. The way I make one is to fill a shaker with ice, pour in about the same measure or vermouth as you have there, but, shake with just the vermouth so that the ice gets a covering, then pour the liquid away.
I then pour in the gin gin gently as to not bruise it and stir it rather than shake it to retain the flavour. Always Noilly Prat dry vermouth and always a top shelf gin.
Stuffed olive or flamed lemon rind is fine, dirtyness is to your own discretion