If your tax return hasn't been processed yet or your e-filed return is still pending, wait at least until the return is accepted before amending.
If your return gets rejected by the IRS, simply log back into your account, and make any necessary corrections.
Here's how to enter your jury duty pay in TurboTax:
TurboTax FAQ: Where do I enter jury duty pay?
You can not simply add W-2 (for your jury duty pay) to your original, accepted return. You will need to amend it.
If you do need to amend your tax return, you should wait to file your amendment until you have received your refund or three weeks from the date of payment of taxes due.
Amend your return:
For more information, please read this TurboTax article: How to File an Amended Tax Return with the IRS