These are some basic tips for beginner bodybuilders. Most of it is common sense really, but nevertheless, critical for someone just starting out to maximize their gains!

1. Stick to Free Weights
There are a lot of machines in the gyms nowadays, but as a beginner, you are interested in putting on mass and building a solid foundation. Dumbbells and barbells are the ticket when it comes to building muscle, especially for the beginner.
2. Do Compound Movements
While you may be tempted to try a variety of exercises, as a beginner, stick to the basic movements. Squats, bench presses, shoulder presses, and deadlifts should not me misses in your routine.
3.. Have a Routine and Stick to It
You need to have a strict routine and follow it closely. Lay out an exact routine detailing the exercises, sets, and reps to perform.
4. As a beginner, do not train every day. Your routine should be 3-4 days a week. Spend the other days for rest and recovery.
5. Train Each Muscle Group Once a Week
While too many days in the gym is counterproductive, too few workouts won't help you either. You need to each muscle group at least once a week.
6. Learn the Correct Form of Each Exercise
This is critical, and one of the biggest neglects beginners make. Correct form is so important to learn in the beginning. Bad form is a habit that is hard to break further down the road!
7. Gradually Increase the Weights
Once you have mastered the correct exercise form, you can start increasing the weights periodically. Keep a log of how much you lift on each exercise, and increase the weight gradually in 2 week intervals.
8. Be in Caloric Surplus
To build muscle, you need to eat more calories than you burn. Use a calorie counter to determine your BMR (basic metabolic rate) and adjust that dependent on how active you are.
9. Eat More Often
Have 5-6 small meals a day, and eat every 3-4 hours. Avoid being hungry.
10. Rest and Recovery
Your muscles actually grow when you sleep. Make sure you get enough sleep every night (8-9 hours being ideal).