When you work out, you 'damage' your muscles trained, and have to take certain steps to regenerate and build them. Experts recommend to allow at least 48 hours between working out the same muscle group; some people like to leave up to four or five days (four days is probably the average). Your muscles don't grow while you're working out; they grow in between workouts. The time between workouts is every bit as important as the time spent working out; during which, you should aim to be getting a good eight hours' sleep, drinking plenty of water, getting plenty of rest and adhering to a suitable diet (0.75-1.00g of protein (milk, beef, turkey, chicken, eggs, protein shakes) for every pound of body weight you have (which could well amount to around 150g of protein, say), and at least 1.2g of carbohydrates (rice, pasta, potatoes etc) per pound of body weight you have. A typical bodybuilder may have a 3000-calorie-a-day diet, and will usually split his/her calorie intake between five or six small meals (this isn't essential, but does help). For maximum muscle gain, it is recommended that you use a weight which you cannot lift more than six-eight times; perhaps the first set will see you lift it eight times, the second five or six, and then you may have to go down a weight, for the third (and often final) set. Three sets of six-eight repetitions is ideal, for each muscle group exercised.
Alcohol can also inhibit muscle growth (which is a real bugger), so, for serious attempts at muscle building, it is perhaps advisable to not drink several nights a week, and to not go too overboard when you do (the negative effects of alcohol intake on muscle growth may be reduced, by drinking plenty of water during/after drinking sessions, as well as having a source of protein when you get home (a shake being perhaps the most ideal source, under such circumstances)).
It's not easy, but good luck.