Argentine tango uses some of the same step patterns as other walking dances, including freestyle foxtrot, paso doble, quick step - and the Texas Two Step! But you can instantly tell these dances apart because of the way the dancers move and relate to their partners.
Practice walking around the room without music, stepping forward onto the balls of your feet, not onto your heels as you do in ordinary walking and in many dances. This should help you to feel like a great jungle cat. Keep this cat image in mind when you're working on aspects of tango style, and soon when you bring up this image your body will automatically move properly.
Now practice walking BACKWARD along the Line of Dance. Turn your head to the side to help you see where you're going. Women should look to the right, men to the left. Straighten your leg a little more than you ordinarily would and reach back a little further than might feel natural at first. This will help prevent bumping knees with your partner when you dance. It also adds to the cat-like look and feel of your walk.
Whether walking backward or forward, keep your weight over the balls of your feet. You can practice walking on tip-toes to more quickly strengthen the stabilizer muscles in your toes, feet, and ankles. It will also help you build the habit of dancing with your weight forward. But when you actually dance don't do it on tip-toes. This is too tiring. It may also get you out of the habit of using your heels, something needed in more advanced tango dancing.