You need to go outside and train more. You'll never reach your potential if you stay in the cozy confines of your gym.
Why? First, you'll never ever see anyone else except those in the cozy confines of your gym. If you're the biggest guy at the "fitness center" with your guns measuring 15 inches around, you might never be inspired to go beyond your current regime of bench, curl, bench, curl, bench, curl. Recently, I saw a young woman do 21 straight pull-ups and immediately decided that I certainly had been dogging this exercise.
But when I say train "outside," I also literally mean go outside!
In past articles, I've written about things like one dumbbell training which is perfect for training outdoors. Grab a dumbbell or kettlebell, put it on the floor of your car, drive out to a nice spot and simply invent a workout. Lift the thing as many ways as you can imagine and do as many reps as your body will allow.
I spend the majority of my workouts outside. Certainly, rain makes it difficult with iron, but I've trained in snowstorms and torrid summer days. I keep a towel on the bar so I don't burn my hands when I grab it, but it's well worth the effort.
Besides, why go to a tanning bed when you can get a golden tan while performing multiple clean and jerks?