Before anyone else can know all that you are capable of accomplishing in life, you have to know it for yourself. You have to see those accomplishments before they happen. You also have to believe that they will happen. You can't have visions that settle for anything less. You can't ever hope to be second best. This will surely lead to self doubt. And you can't look forward to your future with thoughts full of doubt; this will lead to a future with very few accomplishments.
A negative outlook can be such a drain in so many ways.
It will keep you from trying your hardest, it will urge you to quit when times get tough and it will convince you that giving up is an acceptable option. Most of all, a negative outlook will make you care less and less about achieving your goals. That will then lead to a negative version of you, who adds more negativity to the world with each passing day.
But if you allow an optimistic approach to carry you from day to day, your future will be filled with promise.
The hope that lives inside you is fed by a positive attitude. Alongside that hope lives a confidence that grows with every optimistic word.
God has created you to be who you are for a reason. He tells us this in Jeremiah 29:11 "For I know the plans I have for you," declares the Lord, "plans to prosper you and not to harm you, plans to give you hope and a future." So why not believe in yourself every minute of every day? Believe you can accomplish whatever goal you set for yourself. Speak positive words and see the future with a hopeful and confident eye. Maintain that approach and others will also start to believe in you as well. That kind of belief can make anything possible.