The Gin and Sin Martini is good entry level cocktail. You don't need an elaborately stocked bar, you just need a few ingredients and the thirst for a casual martini. If you're religious, don't worry...'sin' is merely part of the name. If you feel the need to attend Confession afterwards, that's entirely up to you.
1.5 ounces of Gin
1 ounce of lemon juice (about 1 lemon)
1 ounce of orange juice
.5 ounces of Grenadine
Add all of the ingredients into a shaker with ice.
Strain into a martini glass.
Sip & enjoy