Wind down the operations first
Before any legal dissolution, the business itself has to be wound down. That means collecting outstanding receivables, paying or settling all liabilities, disposing of assets, and ceasing operations. Any assets left in the corporation when it dissolves are treated as distributed to shareholders, with tax consequences, so you want the balance sheet close to empty before you file.
Disposing of assets can itself trigger tax, through recapture of capital cost allowance or capital gains, so the timing of asset sales relative to year-end is worth planning rather than rushing.