1. Don't whine when you die... or get zerged... or whatever else. That is part of the game, if you don't like it, seriously why are you on a PVP server?
If you /shout any stupid ****, make excuses or say pretty much anything else but GG then you just come across as a sore loser. Is it their fault that they are in a big group? Whitefall is a popular server and people group up in numbers to give themselves an advantage... again this is part of the game and it is a PVP server.
2. Don't gloat when you win... You know how everyone hates a sore loser? The opposite is true. Beating someone is more than enough humiliation and actually it doesn't hurt as much when your victor starts spouting crap because then you know they are an idiot.
3. Don't give up... If you die, respawn, regroup and give it another go. Outnumbered? So what... focus fire and take a few of them down with you. Some of the best battles I've had have been when outnumbered. Plus it's a win/win situation. If you all die, they had a bigger group, and you had the bigger balls and you gain some respect in the process.
In the end it comes down to mutual respect and understanding... Might seem a strange one given how much bollocks is on this forum but the reality is the opposition are exactly like you, there is no difference, we all experience the same PVP game play, the same frustrations. We've all been spawn camped, been zerged, followed and harassed... getting annoyed about it makes no sense.
The best PVP players in my experience are ones that win with humility and die with honor and keep coming back regardless, this is true no matter what game I've played.