There are a lot of servers these days that are PvP based. If your new to online games or just new to MC ill start of with the basics of MC PvP.

First off PvP stands for Player Vs. Player. its very basic stuff. you can fight other players head to head. not some NPC.

Secondly there are many, many reasons that PvP can be frustrating for you. for one thing you can loose all your stuff or someone can just randomly come up to you and kill you. I had this happen to me a lot when I first started but I got used to it and learned some tricks that you can do that can prevent you from loosing your stuff. here are a few

• before going mining or PvPing put things in a chest at your home or in your faction (only if the server your on has factions)
  
• secondly your first priority should to make sure you have armor and a sword. (this is very important)
  
• And lastly make sure your sensitivity is PERFECT. your sensitivity can be the difference between life and death
  

That's all I have for right now hope this will help you survive in any PvP situation.

Comment for anything else that you need help on in servers or PvP. Good Luck!