PvP in EVE Online can take a while to become effective at, and there are a number of factors a player must consider -- both in terms of ship fittings and tactics used -- when engaging opponents. Speed, range, damage types, active tanking vs. passive tanking, when to engage and when to evade, are but a few things that need to be taken into account.
Given this complexity, there are players in the game who've recognized that there's a real need for PvP instruction in the game and offer services to that end. Agony Unleashed stands as EVE's premier PvP school, regularly offering courses that show players how to use a given type of ship to its deadliest potential. Baka Lakadaka, of Agony Unleashed, has written a piece for EVE Tribune called "A Tale of Three Waterpistols" that could be useful to a newer player trying to get a handle on PvP in EVE. Check out his article for a look at how tracking, speed, and optimal range are interrelated in EVE, through the easily-understood analogy between children (of different sizes) shooting waterpistols at one another, and the relative strengths and limitations of different ship types.