If your claim is denied, you should consider appealing it. This will give your case a second chance to be approved.
There are several levels of an appeal. Your appeal will be reviewed by a Decision Review Officer at the VA office or the Board of Veterans' Appeals will review your claim.
The VA will give you an estimate of your initial rating when you apply for disability. If you believe you are entitled to a higher percentage or you were wrongfully denied benefits, file an appeal.