The physical world is interconnected to the ideal world. This is a universal law. Whatever you plant in your mind will eventually manifest in the outside world. The human mind is connected to the fabric of reality. What you think becomes who you are. It’s just like planting a tree, you first gather rich and fertile soil and choose a seed that you would like to plant. You give it enough amount of water and sunlight. When the time is ripe and the season is set, that seed must sprout into a mighty tree. The fertile soil is the mind, the seeds are the thoughts, the water is the action and the sunlight is the feelings.
Energy flows where the attention goes. All energy attracts similar energy. You can not put out negative energy and expect positive energy. You cannot plant apple seeds and expect baskets of oranges. If you are constantly thinking about success or failure, you are already planting that seed. And it has no choice but to germinate.
You become what you think about.