• 4) “veuillez m’aider” is an imperative, like (3) but with a pedantic tone, so it is not polite at all.
• 3) “aidez-moi” is an imperative without the pedantic tone, equivalent to “help me.”. It’s not particularly polite.
• 1) “m’aiderez-vous” is equivalent to “will you help me?”.
• 2) “m’aideriez-vous” is equivalent to “would you help me?”.

The equivalent to “please, help me” is “s’il vous plait, aidez-moi.” It is quite the same level of politeness as (2) but is more used in spoken language, whereas (2) and (1) are rarely found outside written French and sound more literary.