Quick small Guide to world pvp:
Follow raidleader, but stay spread enough so the enemy cant sapper everyone at once.
Pvp gear, nifty stopwatch, pvp trinket or reflector as second, prepopped Greater Protection Potions, Free action potions for when pvp happens, and sapper charges/arcane bombs. (FR gear might become good)
Keep mounted when possible don’t dismount unless call is made to go in. Don’t go by yourself.
Few class explanations because I know from experience some people are not used to 40 man pvp:
Rogue: you might be assigned to scout, information is your weapon not to sap etc  stay informative and don’t die. (Not “40 alliance on me” but “40 ally east of you”)
Hunter: keep track humanoids at all times make sure to communicate if something pops up.
Shamans: resistance totems are CRAZY important. Having 60 more FR against 10 sappers will make 3 of them resist.
Priest: Power word shield spam pre running in. and fearing enemy mages running in are important. Try to dispel death coils on our own mages.
Warlocks keep death coils ready for the first mages running in and RoF down from far away hellfire rarely is possible to get off properly. Try to dot up and potentially Curse of tongue palys and priests if the fight goes longer.
Warriors shield and shield wall ready. Sapper deep and fear. Don’t use your sapper right away since you are likely the class that can survive the longest you can get a better one off than some of the other classes.
Mages make sure to carry invis pots and invis trinket. Having a mage pop up in enemy raid with frost nova BEFORE they can pop fap can win a fight singlehandedly. (Hunter Frost trap can also work though not having blink makes it hard)