Step 3. Open up Skype and get in a call with the victim.
Step 4. Click on Start Capturing Packets and watch the packets roll in.
Step 5. Stop capturing packets and now it is up to you to find out what IP it actually is. There will be lots of different packets, one of them will be your IP4 Address, just ignore that. Before you get in a call with someone, just start capturing packets already and then get in a call with someone and you will see a difference there.
-- You can also do stuff with filtering, but if you use your brain you can easily find it out.