It takes a lot of failed attempts to get good at PK. You can post logs and ask for comments of what you did wrong. Many people will gladly give you their two cents.

You have to analyze another player's build and exploit their vulnerabilities. Know who you are fighting (race, class, spec) and know what to do against them. There are different tactics for different classes.

It's hard to tell you what to do with the information you've given.

The best advice is to play the character you like best, play it to age or con death and learn all you can. That's how you learn about this game.