You can do this anywhere you have room to stand straight up. Make sure there is nothing around you that you could trip on or stumble over. If you can, do this one barefoot (you don’t have to, but you will feel more). Put your feet and legs together. Try to make your body as tall and as stiff as possible. See if you can feel the pressure of your feet contacting the floor. Do you feel more pressure in your heels? More on one side than the other? More in the balls of your feet? You are going to play with where you put that pressure. Start by trying to slowly shift pressure into the balls of your feet, all while keeping your feet fairly flat and your body stiff. Hold that position for a few seconds. Now start shifting pressure from the balls of your feet into your heels. Take your time. You should feel that pressure traveling through out the length of your foot and then gradually into your heels. Pause and hold that pressure for a few seconds. Repeat this 8 to 12 times. Try seeing how far your can shift with out stumbling. Now, try to do the same thing, but shifting from Left to Right. Take your time and really make those transitions gradual. You should feel the muscles in your feet and lower legs really firing up! You will even feel your toes shifting and making moves to keep you balanced!
SPECIAL NOTE: For all the In the Gym: Cable and Dumbbell exercises pick a weight that you can do for 8 to 12 reps fairly comfortably and with perfect technique. After a couple of weeks of performing at this weight and with perfection, on then, move up to a slightly heavier weight that feels challenging once you get to that 8th or 12th rep. Once you feel absolutely confident in performing every rep with absolute perfection, only then, go to a heavier weight that is challenging you through out the set.