Piano is a complex instrument that requires both knowledge and skill. Knowledge is learned by studying and skill is learned by practice.
Learning to play piano is not as difficult as some people assume, but it's definitely not a walk in the park, either. It does require time and effort, and it won't be mastered overnight.
However, with proper guidance and instructions, anyone can learn how to play piano reasonably quickly. You can start to play at just about any age as long as you have time and the desire to learn.
If you want to become a good all-around piano player, then lessons are a must. It's very important to build a strong foundation upon which you will build and improve your skills.
There are many things a beginner needs to learn and understand: from the very basics such as layout of the keyboard, reading music, chords, posture, good practice habits, to many advanced techniques and concepts.
At first all this might seem daunting, but when you break it down into simple logical steps it's quite easy. The most effective way to learn is by taking well structured lessons that are designed to walk you through from start to finish. Proper guidance is very important, so that you don't develop bad habits which can be very difficult to unlearn.
The best way is to take private lessons. Of course, private lessons cost quite a bit of money and require a predefined schedule. If that's a problem, then the next best thing are lessons on DVDs.
The very basis of learning piano is understanding piano keyboard layout. It may look confusing at first, especially if you're a total novice, but it's really quite simple. Get familiar with keys on a piano.
Learning how to read piano notes is not as difficult as most people believe. The musical alphabet is very short - only 7 letters. Get familiar with piano notes and learn that All Cows Eat Grass.
Piano chords are the easiest way to strengthen your playing skills, but trying to memorize them will probably make your head spin. Try to understand them instead.