Balance exercises are a great to incorporate in your strength training regimen. You can increase the difficulty of the moves as you progress. Balance exercises engage everything and strengthens the connective tissues. A stability ball or BOSU are excellent pieces of equipment to have for balance training. Otherwise you can use your own body to challenge yourself. You could start with raising a leg or pressing one foot on the balance ball, while doing curls or presses with free weights. Single leg squats or plank with feet elevated are also good moves to slowly add in. A great BOSU exercise is to stand on it and perform basic movements. Whatever you choose, you will need a focal point and a can-do attitude.