First, you need to choose a piano that is right for you. There are so many variations out there and you really need to know what you want, what kind of music you will be playing, what your budget is, and how deeply invested you want to get into the piano. If you want this to become your lifelong work, you need to consider investing in a grand piano or a baby grand. These are very expensive but are high quality and are the most authentic sounding pianos.
If you think that piano playing will be a hobby or past time, then a digital piano might be a better and more practical choice for you. You can get these for much cheaper and still enjoy features like the pedal and the real piano sound, except you will have more features like volume control and metronome attached. Now, this is also good if you plan to play more contemporary music, as the digital piano comes with added sound effects and beats that you can put in the background, whereas the grand is more for classical music and orchestra accompaniment.
Once you have decided what kind of piano to take, you need to find a good piano teacher. Teaching yourself is possible, but having the guidance and instruction of a reliable teacher is something invaluable. You will be disciplined with a teacher and will see yourself make progress. Teaching yourself requires high levels of patience and fortitude and can often be something you will find yourself wanting to give up on. Choose a teacher who has experience with the piano and who can offer you lessons from the earliest stages all the way to the most advanced pieces of Beethoven.
The first thing to learn about the piano are the scales. You need to memorize the scales in a way till they become second nature. This can be done in two ways, both of which need to be undertaken. Write the scales down on pieces of paper till they are committed to your memory and then do scale exercises on the piano keyboard. You must memorize the scales for the left hand and the scales for the right as they differ. Remember helpful acronyms like Every Good Boy Does Fine Always to remember the right scales and then Good Boys Do Fine Always to remember the left hand scales. Then, FACE and All Cows Eat Grass will help you remember all of the keys in between. Practicing scales is essential because this is the root of all the music that you will learn.
Choose sheet music that you are passionate about. You will find that when learning a new song, the task will become very difficult and trying on your patience. It will be hard to remember all the keys, to move your fingers in the right way, and to get a hold of the beat. That is why if you choose a song that you are very passionate about, you will be motivated to learn it and motivated to hear it. This will then make you work harder to get it mastered. If you love pop music, classical, jazz, country, rock, no matter what your preference, choose something you love and you will see that you learn piano that much faster.