I have been scouted what should I do?

It depends who scouted you. Talk to your alliance leaders to let them know and they may want to contact the alliance of the other player if there is a NAP in your state. If you believe you are likely to be attacked then you can shield or move.

To reduce the chances of attack make sure that you keep your resource levels (at the top of the screen) below the protected levels but using them up or transferring them to the alliance warehouse. This way you will not offer any incentive for an enemy to raid you.