You can create a document with Excel or create a document everytime you do a bounty or airdrop.
I prefer the excel sheet solution.
Create cells in which you will write thing like :
-Airdrop name
-When you did this airdrop with day month year
-When they will pay you
-How much points/tokens you have to receive
-Their contacts (In case you don't receive your tokens)telegram, facebook etc..
-If they payed you the tokens
-What do you do for receive this bounty and where
Then, you will write below to this cells the answer to them.
Example: Airdrop name
Lolo
And so on!

Ps :Try to use the same mail, telegram username etc for join airdrop or bounty because they will ask you for take part to it and for verify that you have really joined their airdrop/ bounty.