Yesterday I got my first D&D game on Skype.
I had a blast, even if the conditions were far from optimized.
This spurred a reflection on what is needed for an enjoyable gaming session on Skype.
Obviously, you need PCs and a good connection ON BOTH SIDES. If the connection is crappy, then you won't be able to enjoy the game due to constant delays and poor image resolution.
It's also good if you can arrange a test beforehand. Don't forget to set up and connect the accounts before actually meeting for the game.
If you're hosting the game, the best place to put the computer is in front of the Dungeon Master's screen. This way the Skype user can see the rest of the party: often communication is made also by facial expressions and gestures.
Loudspeakers are a good addition, since sometimes the caller voice is rather feeble.
You should also consider ambient noise: keep it down to a bare minimum. Also chit-chatting on non-gaming topic makes understanding gaming-related talk difficult.
On the guest side, a headset with microphone is needed to keep resonating noise down. You also should be aware of where you are calling from. A silent place is to be preferred to a noisy one.
Having paper reference sheet and books helps in getting all readily available when needed. Also real dices and a dice tray are better than dice-throwing apps, since the results are readily shown on Skype.
Snacks and beverages are to be kept at arm's length, along with glasses. Remember to shut off your mic when eating, otherwise the chrunching sound can annoy people at the host place.
Those are my 2 cents for now; I hope to have more tips for you soon. Enjoy your gaming!