(1) Not knowing what 'Natural Talent' means. Basically it refers to such natural abilities such as Singing, Playing a musical instrument, Drawing Cartoons etc..
(2) Not believing such talents can or should be used by God. The Bible shows God moved through the natural abilities of people as they yielded it up to God. King David had the natural ability to use the sling and play the harp. He ended up with a huge and powerful army and plans for a huge worship center (The Temple). He knew the secret of moving in his God-given natural ability.
You will find God has 'equipped' you with just the right abilities in line with your vision and calling.
(3) Having a low self-image. Fearfully hiding our talents (See The Parable of the Talents.) The one who hid his talents was fearful and afraid of taking risks- the others had more and therefore received more.
Ask the Lord for courage to step out and take risks for Him!
(4) Self-Deception - you may be stepping out and moving in abilities you may not be naturally good at! Sometimes pride can deceive us and we become over-confident. Ask others you respect for an honest appraisal of your talents, receive the truth in humility.
(5) Skilled but not anointed! All talents must be offered to the Lord to be either taken away never to be trusted in again, or broken and blessed and given back to you with His anointing.