If you reach RMD age, you need to withdraw from your RMD accounts. Otherwise, the penalty is up to 25%.
Withdraw your interest and dividend from your taxable accounts, interest is taxed at your ordinary income rate, but your dividend is taxed at lower capital gain tax rate, 0%, 15% or 20%.
If you have maturing bond and CD, cash in them.
Sell your investments from retirement accounts 401k or 403b,or from Rollover IRA to generate cash.