You focus too much on what you don't want or negative thoughts. The Law of Attraction works by attracting what you focus on, so if you focus on bad things happening then guess what? That's what you attract. Negative thoughts or limiting thoughts have the same effect as positive thoughts or limitless thoughts - they both cause what you are thinking to be manifested. What you believe in is what you will attract to you. In a poem by the little known poet Walter D. Wintle called Thinking the famous paraphrase has evolved as quoted by Henry Ford -Whether you think you can, or you think you can't--you're right. You need to always keep your thoughts on the end result or as Napoleon Hill says, your definite purpose! By changing your focus to what you don't wat that is exactly what you will indeed get.
You have limiting beliefs. This goes along with focusing on negatives. Maybe you were told as a child that the only way to get anywhere in life is to work hard or that being successfull takes sacrifice. Maybe your belief about money stems back to Sunday School teachers with their "money is the root of all evil" passage from the Bible. Believe me when I say that is not the actual Bible passage. Look it up, it's 1 Timothy 6:10. I will tell you that it actually says that the "LOVE of money is the root of all evil". (King James Version) Sometimes we need to step back and take a look at thouse things that we have have come to believe in our lives. What others have experienced in their lives are their beliefs - we need to change our beliefs by changing our thoughts about them and create new beliefs. You will not attract what you want in your life unless some of your limiting beliefs change. Dr. Wayne Dyer had a great quote that I use almost every day. "You'll See It When You Believe It!" Remember also that when you change the way you look at things, the things you look at change. Another Wayne Dyer quote!
You stop visualizing. To me, visualizing what you want to attract is a HUGE part of the Law of Attraction. I tell my students they need to be able to see, feel, taste, touch, smell, etc. whatever it is they want to attract into their lives. When you stop visualizing or don't write down what it is that you want, you tend to let your thoughts wander to why you can't have those things. Take time to imagine everything about what it is that you want in your life. Write it down. Draw pictures of it, cut out pictures from magazines, create a collage of the things that you want or the lifestyle that you imagine. By visualizing you keep your mind ever on the path toward that which you want to attract.
You worry rather than letting negative stuff go. Things will go wrong and negative thoughts will come to you. (We ALL have them.) When you worry about anything you give it power. You need to do your best to stop them and get your thinking back on track and away from the worry. When negative thoughts lead you to worrying you need to change them like channel surfing on your TV when you can't find a good show. (And we all know there are more than enough other channels to go to.) Do the best you can to think of something that is positive and more in line with the end result you are wishing to attract. If your want to attract money into your life but you keep worrying about running out of money or always being in debt, stop and imagine that your wallet is full of money and your bank account has more than enough to handle your current and future bills.
By changing these things the Law of Attraction WILL work for you. In fact if you are doing these things it already does work - just in reverse. You are continuing to attract the bad stuff rather than what you really want.