You have to believe in yourself first. If you don’t, no one else will. In his book An Iron Will Orison Swett Marden wrote:

The man without self-reliance and an iron will is the plaything of chance, the puppet of his environment, the slave of circumstances. Are not doubts the greatest of enemies? If you would succeed up to the limit of your possibilities, must you not constantly hold to the belief that you are success-organized, and that you will be successful, no matter what opposes? You are never to allow a shadow of doubt to enter your mind that the Creator intended you to win in life’s battle.
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The world takes us at our own valuation. It believes in the man who believes in himself, but it has little use for the timid man, the one who is never certain of himself; who cannot rely on his own judgment, who craves advice from others, and is afraid to go ahead on his own account.
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Those who have accomplished great things in the world have been, as a rule, bold, aggressive, and self-confident. They dared to step out from the crowd, and act in an original way. They were not afraid to be generals.

It has often been said that fortune favors the bold. Why would that be? Is it some cosmic plot against the shy? No. The answer is simple. Fortune favors nobody at all. It’s an illusion. One reason the bold have more success, the reason they appear to be more fortunate, is that the bold are more likely to get out there and try things. You cannot succeed until you have taken at least some action.

You are as capable as the next guy, so get out there and give it a try.

The other reason fortune favors the bold is mentioned in the quote. The more you believe in yourself, the better you hold yourself, the more confidently you speak, the more others will have confidence in you. If others believe you are capable, they are much more willing to help you.

So go ahead and manufacture some luck for yourself: Be Bold.