“I'm looking forward to seeing you.”

You've made plans to visit a friend that you haven't seen for a while. You tell them:    

I'm looking forward to seeing you.

look forward to (doing something)

This is a polite expression for saying that you're excited about something that's going to happen. But it doesn't sound very strong. If you really want to sound excited about it, try "I can't wait to ___"

"I can't wait to see you."

You can also add adverbs like "really" or "so":

I'm so looking forward to seeing you!