PROOF OF INCOME/FICO SCORE

Since we have been self employed for a small period of time. Do we need to provide anything else to prove our income besides our tax returns? Also my husbands fico score keeps raising every month, but mine has been the same for the last 3 months I have pade all my credit cards to a zero balnce and only one one installment on a car loan. Any advice on how to keep raising my score to atleast a 700 I have been at 677. Thanks