Want to get started in playing against different players in PvP? There are a bunch of simple rules that relate to PvP, and a few habits that good players keep in their head.
Knowing how to play your class is critical in PvP. If you know your class well in PvP, you can win in PvP. You need to know your class well, know when to make use of your skills, and know how to counter attacks. It is important to know the best times to run, fight, or use special talents to get out of trouble. You need to spend time memorizing your talents, and seeing when to use them, so when the time comes for a PvP, you are prepared.
It's also very important to know what other classes can do. Getting to know other classes abilities in PvP can be very helpful, because if you see them do something, you can already have in your mind, the counterattack that is best for the situation. Once you have some experience, you won't stand there stunned after an attack, you will have a plan of action for the most efficient counterattack.
It's important to remember that in the story line, there are two groups. The Guardian group attempts to diminish the Rift power, and the Defiants try to get rid of the Rifts. It's a tough decision to make. The groups are also split into races in each group. There are also callings, and this decision I believe is the most important decision you'll ever make in the game. The role you choose will decide what things you will be good at forever.
There are a bunch of great step-by-step guides that will help you win at PvP. There is this one site I will recommend to you because it has a TON of free information about leveling, PvP, etc. in Rift, and in my opinion it is the best resource you can have for playing Rift right now. They put up an article every single day, and it's always very helpful. The article I'd recommend checking out is the Rift Tank guide or their Rift PvP Builds article.