basic plan...if u dont know already have one...
day 1...chest and triceps
day 2...back and biceps
day 3...shoulder, trapezius and abs
day 4...legs...if u are concerned with lower half
then take a day off or so and begin the cycle over again.
ex...for chest and triceps:do 3 different chest exercises with 3 sets of that exercise. So 12 reps the first time, bump up the weight a little, 10 reps, then bump up the weight a little and do 8 reps. Triceps ...you could 2 different exercises for it...even 1 is fine because when you are doing chest you do use triceps since it compliments the chest.
Buy yourself a 5lb container of whey protein...brand does not matter...make sure its not weight gainer. Drink one for breakfast, one after the gym and before you go to bed.
I guarantee you will notice a real difference in 1 month. After that it gets addicting because you like the improvements so much. I know I did. As time goes by, you'll get good at it and you could adjust the workout to better assist you in your goals. Gluck.