[T]he government’s interest in veterans cases is not that it shall win, but rather that justice shall be done, that all veterans so entitled receive the benefits due to them.” Barrett v. Nicholson, 466 F.3d 1038, 1044 (Fed.Cir.2006)
VBA21 -4138: Statement in Support of Claim: a statement from a fellow veterans who saw you in some activity, observed your accident, illness or knows of typical situations. Your doctor's letter (remind them to make positive statements, not "may have" or other inconclusive & vague stuff), your wife, anyone who can add info. Professional opinions must be phrased "his condition is as likely to as not be caused by" etc. as the weakest wording, and "with medical certainty"-type language if possible.