[Year's_End]

You want to focus on your core more than anything else as you're getting started, and don't stack all of your muscles into a full body workout in a single day. You need to split it up and focus on individual muscles or groups that work together.

First of all, your core needs to be strong in order to properly and efficiently build muscle mass and strength in the rest of your body. Building up a strong back/chest/mid-section is vital. Don't bother singling out your vanity muscles (biceps and triceps) until you've established a solid building ground or you'll pay for it later on by some degree. Besides, you'll work those out doing other compound exercises.

If you can't dedicate individual days to one or two specific muscles, try splitting it up into at least three different days with main groups. For example, separate your upper and lower body. Split your upper body into push/pull days. Push days include your chest, triceps, front deltoids (shoulders) and front core exercises. Pull days incorporate your back, rear delts, and biceps. Leg days are self-explanatory.

You'll see much bigger gains this way than doing full body circuit training every time you go to the gym.