The next time you're at the gym/club, take a look around. Are there people there that look exactly the same as they did a few months ago? What part of the gym do they workout in? What equipment do they use? Now, find the fittest and strongest looking people in the gym. Where are they and what are they using?
The people who don't change are probably using a lot of weight stack machines. The people that look fit and strong are most likely using barbells, dumbbells, medicine balls, kettlebells and weight plates.
This is not to say using machines are bad. They can be great tools for achieving success working out. Machines are great for isolating muscles, adding a bit more when you are toward the end of a workout, or for advanced techniques.
However, using free weights needs to be the basis of workouts. By standing up, you are using more core muscles and stabilizing the weights. This will lead to greater overall strength. When you are stronger, you can build muscle better. At the same time, by incorporating more muscle use during your lifts, you are burning more calories. This will help lead to a leaner look as well.
So, you choose, who do you want to be? Do you want to look the same? Is thin but flabby OK? Or do you want to look strong?
You don't have to get huge like some of the guys/ladies you see at the gym, but you can find a happy middle. Ladies, think Michelle Obama arms. If you want to look strong, lean and fit; head to the free weights. This will lead to rapid improvements.