Never “wing it” for your workout—always go into the gym with a plan developed beforehand. Your workout needs to be tailored to your training and fitness goals. If you consider yourself a novice and are unfamiliar with programming the right workout routines for your training goals, then take a look through the Muscle & Fitness website for countless articles on workout plans and how to build a program that fits you.
Drop the ego—if you’re a beginning lifter, then you need to start with lighter weights to perfect your form, technique, and to develop the motor skills that will allow you to move on to bigger weights. From there, you should be progressively overloading—not 100 pounds at a time, but in smaller increments that you are able to move with control and proper mechanics. Otherwise, you are setting yourself up for potential injury and you will not be developing strength properly.
Overtraining is a real problem. The body needs time to heal and recover, so going to the gym seven days per week is simply unnecessary and counterproductive. Start with three days per week to ensure that you provide yourself ample time to eat, rest, and recover.
Water is essential for an effective workout, and not drinking enough will impact your strength, stamina, and condition. A good target would be to drink half your bodyweight in ounces of water every day.