This was my exact question when first hearing about the law of attraction, and to be honest, altogether, it is all in the name. For me it is easy to explain it like this: the law of attraction is exactly how it sounds, its is the law that attracts to you what you think it to, so if you hope for wealth, think wealth, believe wealth, drown yourself in positive thoughts of wealth, and those very thoughts will be like a magnet and bring all of those thoughts to you and into reality because it has no choice but to do what you have thought it to do. Kind of like your own personal massive computer, you type in a command and it will do that exactly.
This law works in only one way, and that is to carry out what your mind thinks it to, so you have to remember to keep thinking positive. Many people live their lives with negative thinking, and this only brings negative experience into their lives, you have to erase the negative. Positive thinking and believing in the law of attraction is where you will benefit the most from this universal law.
Everything you see and know is made up of the law of attraction, the sky, the air, and the oceans are all made of this law. The things that tells you that you if you plant a seed, something will grow, that is the law. A couple of things that are very important to remember is that like attracts like, so like thoughts will attract like thoughts. So if you are thinking negative thoughts then those thoughts will become your reality, keep it positive. Using the law of attraction will take time and practice, you will have to train your mind to have the positive thought wipe out the negative ones.
