I'm a UK player and
all of my games are with people who are not in the UK. Until somewhat recently my computer was part of the problem with an older skype and certain accounts for games etc locked.
With a slightly upgraded OS/Parts and a reasonable connection and an up-to-date Skype I've found my calls have improved to a reasonable level with issues being if a player is in the bad parts of America or in Australia.
In a FPS this translate from old pings being around 240 and current pings being 110, in vocal communication over skype this isn't so bad providing people let you speak; if skype is failing you I would recommend switching to a hosted service like teamspeak or ventrilo/mumble or discord. This will provide an easier joining time and hopefully remove some of the lag.
The biggest tip I can provide ( in the cases of those with old skype still ) is they have to Host. Period. New skype connects to old - not the other way. Also, if someone is in the bad part of America ( of whom have yet to be upgraded to modern standards ) do not like them or someone out of America host the call. Find the middle person and have them host it.