Success in weightlifting requires a very specific mindset. It requires absolute belief in one's self. Not just a positive mindset. Not just a feel good mindset. Not just an "I know I can" mindset.
It requires a short memory. It requires that you forget about past failures. It requires that every time you approach the bar, deep in your soul, with everything that is in you, with every fiber in your being, you absolutely know you are going to succeed. Anything short of that, and you are destined to fail.
This is true in training, and on the competition platform. On the platform, you must forget about all the struggles and bad days of training. You must believe that you have worked harder than, and struggled more than everyone else. You must believe that everyone else wasted their time and money to be there. That bar is yours. That platform is yours, and you are about to put on a show. Everyone else should have stayed home.
This is not an arrogant mindset, but one of extreme confidence in your abilities, and the work that you have put in.
You must have a strong mind.