Introduction: Tango. This dance has two special features. First, the frame is different from normal ballroom frame. Second, with regard to the beats, you are operating on a 6-count basis, but the music proceeds as a 4-count. Hence, it will take 3 bars of music to match 2 Tango Basics.
Frame: Tango. Count: SSQQ, SQQS.
Leaders and Followers: You move as one unit (don't you always?). However, do pay close attention below. Frame, CBM, and how your feet land are all EXTREMELY IMPORTANT. That's why the first section is devoted to explaining these three concepts before we even begin teaching the moves.

Frame (Leaders and Followers)
In Standard Frame, there's some space between the couple. The leader's hand is on the upper back, near the shoulder blade. The follower's left hand is at the leader's deltoid. In Tango Frame, you are much closer. The leader's hand is now in the follower's small of the back. The follower's left hand is now hooked behind the leader's right arm, with the left thumb hooked into the leader's armpit (no, armpits are not that disgusting. Unless he's got sweaty armpits).

In such a frame, there's almost no space between the couple. So how do you move? Well, your lower body is such that you do have room to move. Stand with your feet together. Go onto your toes, and land your feet at a 45 degree angle, relative to how your feet were originally. Bend your knees. your left foot should be slightly ahead of your right. That's Tango frame. In tango, you are never elevated. Elevation is for Quickstep and Waltz.

Regarding feet position, in dances such as cha-cha or rumba, the leader's left foot is directly in front of the follower's right foot and the same is true for right foot and left foot. But in tango, you are slightly off-centered. The leader is slightly right of the follower (and consequently vic versa).

Contra-Body Motion (CBM).
What is CBM? As per Wikipedia, "CBM is turning the right side of the body towards a left moving leg OR turning the left side of the body towards a right moving leg. The body and the leg must move at the same time, and not one after the other. CBM occurs on forward or backward steps only (or diagonal steps which still feature forward or backward movement), and not on side steps."

So, what do we take away from this? In tango walks, you are never walking straight. Because of CBM, you are always curving your steps. Now, how much curve? That's dependent upon you, your partner, and most importantly, the situation. If you're negotiating a corner, you will probably want to curve your steps a little bit more. If you're traveling down the side, not so much. This will become clearer below.

Walk Normally. Heel-Toe, Ball, Toe-Heel
Tango is basically walking. Except it's a little harder than that. Pay very close attention in the instructions below to see how your feet landed. Keep in mind, that in Tango, you often land Heel-Toe. There are a few exceptions. In some cases, you will land on the ball of your foot. And when walking backwards, toe-heel (because there's no other way to do it).

Instructions (Leader Perspective)

2 Walks and a Link (SSQQ)
Start with your feet together, your knees in the position described above. You are 45 degrees off line of dance (DW).
Slow1: Left leg steps forward. As per CBM, this step is curved. Heel-toe. Remember, you are in a lowered position, but keep your back straight.
Slow2: Right leg steps forward. Heel-toe. Right leg goes between the follower's legs.
With the 2 slows (walks), timing and communication is crucial. It takes a while to be able to move in sync with a partner, so just keep on practicing!
Quick1: Left leg steps forward, land on the ball of your foot. Your weight is now (temporarily) on your left foot.
Quick2: Right leg steps (ball) such that both feet are along line of dance. At this point, you are in open frame. In theory, you place your partner to be parallel to you, but your partner can also help some by being receptive.
Transition from Closed to Open: During the Quick1, as per CBM, your right shoulder is ahead of your left leg. Don't actually do this, but imagine yourself twisting to the left via CBM. During Quick2, you untwist and consequently, place your partner exactly where she should go. At this point, your left arm (and the follower's right arm) is extended horizontally (slight bent in the elbow), pointing in line of dance.

Closed Promenade (SQQS)
This is right after 2 walks and a link. You are now in Open Position.
Slow1: In 2 walks and a link, you shifted your weight from your left foot to your right. Now, you take a slight step along line of dance with your left foot. Heel-toe. Your weight shifts with it as well.
Quick1: Right foot crosses over in front of left, along line of dance. Heel-toe.
Quick2: Left foot moves behind right foot. Heel-toe. Now, your left foot doesn't move along line of dance. Instead, you step diagonally to the center (45 from LoD, but towards center, unlike DW, which is away from center). This is so you can get back to where you originally started.
Slow2: Right foot comes next to left foot, you are now in the original position that you started in, along line of dance. Heel-toe. Place your partner! Don't leave her behind!

Instructions (Follower Perspective)
Exactly the same as the leader. A difference is, you never have to worry about your right leg stepping in between the leader's legs. That's a leader thing only. In addition, when you're walking backwards, you can only do toe-heel (again, for obvious reasons). But when doing closed promenade, you should also be doing the heel-toe stuff.

Tips and Tricks
  • Walking. Tango can be thought of as walking normally. Of course, it's not that easy. But just keep in mind that you're often doing heel-toe when you walk and that you should be in continuous motion.
  • Upper Body. Frame is HUGE. A weak and disjointed frame = trouble. In tango, you move as one unit, and a good frame is key to that.
  • Timing. Related to walking, timing is super-duper important. If the leader's leg moves too early, there's going to be a clash. If the follower moves too early, there's an awkward space. Work with your partner to get the timing of the leg movement down.
  • Curving. As said above, how much you curve in your walks is dependent upon you, your partner, and the situation. But regardless of how much you curve, you're always curving, even if only a tiny little beat.
  • CBM Part 2. To help you with CBM, think about walking normally. When walking normally, you go through heel-ball-toe. Now, in CBM, you walk on the outside edge of the inner foot and the inside edge of the outside foot. Try practicing going in a circle with this type of CBM.
  • Tempo and Beat. Remember, 2 quicks = 1 slow. And 1 beat = 1 slow. Listen!!!
  • Nose and Toes. Your nose and toes should be pointing in the same direction as where you will be walking. This is true for walks, closed promenade, etc.
  • Booty. Don't stick your butt out. Bend your knees (slightly), not your back.
  • Let there be Light. Placing the legs. Followers, if there is no room between your legs for a leader to place his leg between walking, that's bad. You don't want the space to be huge, but if it's nonexistent, the leader can do absolutely nothing about it.