Access your statement, either online or through the mail. You should always compare the statement with what you have recorded in your check register to ensure that the information is correct.
Find the checks on your statement. They will be easy to spot because the check number will be listed with the amount and date. These dates reflect the date the check cleared your bank, not the date you wrote them.
Review the checks and make note of any that you have written, but do not appear on the statement. These have not yet been deducted from your bank balance.