If you're an adult who thinks you have 2 left feet, there are 3 things that are most likely holding you back - Self-Consciousness, Learned Muscle Patterns and Rhythm.
Self-consciousnessMost people have heard the saying that starts, "Dance like nobody's watching...". It's human nature to dislike looking foolish. When we're learning something new, we hate having an audience watching our silly mistakes. Dancing feels so public - we're standing up in the middle of a crowd of other people, making big movements - surely everyone is watching us?
The standard teacher's answer for this is, "don't be silly, everyone else in the class is too busy worrying about their own mistakes." I've been guilty of saying that myself - but it's not always true. There will be times when other students are watching you - it's up to you to take your opportunities to watch them. Chances are, you'll find you're not the only one struggling with the steps. If the thought of embarrassment is holding you back from starting a dance course, a good solution is to buy a beginners' dance DVD and use it to learn the basics before enrolling for your first class. That will help you get over the first hurdle.
My Brain understands But My Feet Won't WorkThe second thing that holds adults back is muscle memory - the patterns of movement that we've learned growing up. Your body likes doing repetitive movements - stuff it already knows and doesn't have to think about. Dance requires you to move your arms and legs in strange and unusual ways. Your eyes may watch and your brain may comprehend, but it can take a while for it to direct your limbs to interpret these new and unfamiliar movements. Be patient with yourself and understand it's the way your body works. Eventually, these new movements will become part of your muscle memory, too, and you'll be able to do them almost without thinking.
It's Not You, It's MeIf you've tried to learn dancing and failed miserably, don't be too quick to give up. In dancing as in any other skill, there are good teachers and bad teachers. Someone can be a fantastic dancer but a hopeless teacher, and vice versa. For instance, Margot Fonteyn was one of the greatest dancers in the world, but she couldn't teach. Whereas Dame Ninette de Valois was never a great dancer herself, but her ballet classes were among the best.
So if you joined a school and didn't learn very much, ask yourself - could it have been the teacher at fault, not me? Different people have different ways of learning. A good teacher should take that into account. A good teacher should be able to explain steps, not just demonstrate them, and be able to correct students who are making mistakes, without making them feel picked-on.
The other possibility is that you picked a style of dance that doesn't suit you, or was too technical. If you've never danced before, the complex rhythms and fast footwork of flamenco would be too much of a challenge as a first dance style. If you're inflexible, I wouldn't recommend ballet or jazz to start with - do some yoga first, or pilates. A good starting point for most people is social dancing like Ballroom, Latin or Street Latin and Swing. You don't need to bring your own partner - most schools rotate partners so you won't feel left out if you're on your own.
I've Got RhythmThe final - and unfortunately, the biggest - stumbling block is rhythm. Going back to those dancing children - they all dance when the music plays, but you'll notice that some dance in sync with the beat, whereas others bop around with no reference to the rhythm. Those children who keep time without thinking are lucky.
A lack of rhythm is by far the biggest obstacle to learning to dance - but it's not insurmountable. Rhythm can be learned. However, trying to learn to keep time and master dance steps all at the same time is too much new information at once. If you have no rhythm, it's easier to fix that problem first - then graduate to dancing when you begin to feel the beat.
If you have a friend or family member with a good sense of rhythm, get them to sit with you and clap along to music - any music. If they can't spare the time, get yourself a metronome and ask them to set it to the right tempo at the start of each track, then clap along with the metronome.
Learning a musical instrument is a good way to learn rhythm. When you read music, you can see the rhythm on the page while you play, and many people find that helps.
If you don't have the patience for all that and want to start dancing straight away, then pick a style with easy steps and simple music. Ceroc or modern jive is one of the easiest, because it uses pop music, which usually has a 4/4 signature and a loud bass beat. Steer clear of Latin dances (Salsa, cha cha, rumba etc) because the music is almost always syncopated, and that's the hardest type of beat to follow if you're not rhythmic. The exception is Merengue, where the footwork is basically marching to music.
Dance can be a very rewarding and enjoyable hobby. Be patient with yourself. And remember - it's never too late to learn.