This is from the official SOE forums, I am simply copy pasta!
(they are good tips)
Basic Combat Know How
Break Free:
If you did the tutorial there is a section with a yellow device stuns everything around it and your told to " tap " block to break it. What ISN'T made clear is just what a break free can do, and its general cost. A break free costs power, it breaks most control effects, by tapping the block button will knock enemies are close away and makes you invunrable to same CC attack for a few seconds.
Effects Broken by Break Free
Stun/Hard Stun(must press Sqaure to break a hard stun!)
knock up/down/back
Encases
Levitation
ect
pretty much EVERY effect causes loss of control can be removed with a break free! Its most basic pvp defense learn to use it, but do be careful not to abuse it. Spamming break frees can result in you having no power, in which case cant use a break free again and are at mercy of the enemy!
General Combat
Next i'll discuss general combat, this is how combat system works. Think of Combat as Janken or rock paper scissors! This is premise of the system and understanding general concept behind it is probably next key step into becoming a good pvper. First lets discuss basic attacks, and combos and defenses and how they interact with each other.
Offense
Interupt: and interupt is a combo almost ALWAYS a melee strike, such as various lunges in game. An interupt is just what sounds like its designed to interupt a charge or channeled power. Using this power while enemy is charging causes them to become hard stunned. Thus an enemy channeling an attack like say full auto from dual pistols, will be stunned for trying to spam that ability.
Block Breaker: this is an ability usually requires a short charge or is channeled this is not always the case! some block breakers specifically high tier ones can actually be instantly fired but usually have a short range(an example would be rifles flame thrower). A block breaker is just what sounds like, if enemy is blocking and you use a block breaker it causes them to become hard stunned punishing them for blocking your attack. These attacks typically can be interupted but not always. If some one is spamming block be sure and counter with this move!
Defense
Block: block reduces incoming damage by 90%, and if you block an interupt causes enemy to fall down and have to stand back up. While standing up enemy can not defend or counter but can break free of the effect, it also causes a small amount of damage. Blocking interupts is a basic skill you need to master, but be aware that block breakers will hard stun you so use it only when your sure what attack enemy is using!
Roll: Roll is a defensive move, that rolls away from enemy is a short delay on all combat when you finish a roll. Roll can avoid some attacks it is a belief by many that roll spamming can avoid any and all damage to your character. Let me reassure you THAT IS NOT THE CASE! yes most attacks can be avoided but, if you lunge during the roll you will hard stun the roller. if also time your block breaker as they exit a roll can catch them blocking as well. Both are perfect counters to a roll!(edited do to my friend blackstar pointing this out to me).
Passive Resistances:
a lesser known function and something that can help in the defense against control effects. every travel power has a " passive " resistance to various CC's its differant for every CC type. For example flight has a passive stun resistance can really help if your finding stuns a problem. This is even better for a tank since it boosts your already high passive CC resistances! in addition is also a final talent below the resistances that causes you to " regenerate " power anytime you break free of that effect. Its power over time and as i recall usually less power then you lose, BUT it helps soften the power loss when your getting CC spammed or breaking alot of controls.
Control Effects
Honestly arent alot of controls need mentioned is one i will elaborate on as alot of debate about them that varies. Controls are effected by dominance stat, more have harder it is to break free from that person.
Encases:
encases are any attack that put you in a bubble or block or object and allow you to be weaponized. Like most CC spamming block will break it, your also highly resistant to most attacks HOWEVER are certain attacks will cause high damage to encased targets. An additional note on encases, if you melee strike an encased target you actually reduce the duration of the encase, making it easier for them to break free. Only hit encased targets with specific attacks that can hurt enemy in the encasement. Also, be careful when dealing with round ball encases, they are a physics object if you try and hit them with a melee strike it WILL send them rolling down the street! this can be used both to avoid doing it or to do it and get that person out of the area. I'm also not posative but i believe your allies can " hit " your encasement and help break you out of it.
Stun:
Stuns are just what they sound like, a move that causes you to be unable to move or act. Are two kinds of stuns basic stun is removed with a break free, Hard stuns will have own section. Should be noted that stuns stack with each other at present doing repetive stuns increases duration, its debated if it also increases break free metor or not, my friend says no i say yes no one knows yet i think.
Hard Stun:
this is a stun from powers or melee counters ie block breaker while blocking or interupt while charging will cause a hard stun. Hard stuns require you to spam sqaure button(melee attack) and reduce meter down. They are currently considered STRONGEST form of control, are most highly debated effect. Some say are to strong while others think they are fine. I personally find the button hit to remove it counter intuitive but easily delt with. Over all this effect will be one will drive you insane!
Knock up/down/levitation: these attacks essentially lift you into the air and suspend you there, or knock you around the field. Are probably most common form of CC can easily be removed with a break free and are least bothersome of all CC.
Grounded:
are a few effects cause the grounded effect this can not be removed! it supresses your movement power, and renders you base movement for the duration.
How To generate power easily!
This is a basic skill i think is important for pvp, remember the following! power regen is NOT based on damage but rather how high your combo rating is! by generating the highest combo rating possible you can keep your energy flowing! this is harder for tanks and controllers who have to constantly be using there energy in large quanities, but you need to keep your combo rating high as possible! healers typically will spam there ranged attack and build there combo that way! this is important in pvp because with out energy your useless to your team!
Advanced PvP Knowlege
Know your Weapons!
its FAIRLY important if your going to pvp seriously, to Learn each weapon in depth since i've played most weapons to lvl 10 i have a better understanding of every weapon set. A common thing i see in pvp is blocking weapons are almost entirely block breaker based.
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