Signal to Potty?

Is there a way for us to train our dog to give a signal to go outside to potty or will this be something she'll show us on her own? She doesn't let us know at all and there have been two accidents this month. She's 8 months. I take her out after eating, sleeping, playing, and about every 3-4 hours if she's not active. I would really like to show her how to give a signal if that's possible.