How do i start a signature campaign for a coin. I have not done this before.
Please elaborate your question. It's not very clear what you are asking for.
Do you want to participate in signature campaign? If yes, please read these guidelines before joining campaign:
https://bitcointalk.org/index.php?topic=1684035.0Here is list of all Bitcoin paying signature campaigns:
https://bitcointalk.org/index.php?topic=615953.0As you see, there is not many open campaigns now. You may look at Bounties section if you don't mind to get payments in altcoins/tokens.
If you want to start your own campaign, you need to have budget for payments, signature codes and campaign manager. But I doubt that you planning to start your own campaign, it's more likely that you want just to join one of already existing campaigns