There are four possible roles for you to choose, each having its strengths and weaknesses. Each role has a penalty stat, which requires 2 chi points to raise that attribute by 1.

Warriors have access to the best melee skills, and have the most number of hit points.
Strategists have excellent support skills.
Exorcists have access to powerful ranged skills.
Holists average over all the other roles.

You can find several possible builds by clicking on the links above.
The different roles differ not only in their skills and penalty stats, their attribute points also confer differing amounts of benefits (e.g. dmg, hp, ve), as shown in the attribute chart.

Builds

Apart from your role, your character's build plays a siginificant part in determining the strengths and weaknesses of your character in various situations. A good build goes a long way in increasing your efficiency in pve, or your ability to take down opponents in pvp.

Good builds generally avoid placing too many points in the penalty stat, using relics, elixirs, clothes, weapons and other accessories to make up for the weakness in that area. Generally speaking, if your penalty stat is constitution, a relic that adds 6 to constitution is better than a relic that adds 10 to dexterity, for the 6 points in the penalty stat works out to be the equivalent of 12 chi points. It is better for you to spend 12 chi points in dexterity and use a relic that gives 6 constitution, than spending 12 chi points in constitution and use a relic that gives 10 dexterity - you get 2 more dex in the 1st case.

Please read the Note on Builds if you require further explanation on certain aspects of the suggested builds.

Roles and Equipment

Apart from attributes, the correct type of equipment can make a significant difference to your performance both in pve and pvp. The optimal equipment, given your budget, need not always be the weapon of the highest refinement level, or WD weapons for that matter. A good balance of the correct type of clothes, weapons which shore up certain areas in need of improvement, accessories and hp/ve absorbing items can greatly improve performance at the same cost.

Healers and hybrids have little use for hp absorbing items for example. It is not the most worthwhile for them to invest in hp trinkets, RL/GB/EC WD weapons for grinding. A well-refined weapon giving high damage will work better. That said, it is more pressing for them to obtain ve absorb clothing before going for better weapons. Warriors, on the other hand, will find that hp absorb items boost their grinding abilities much more than high damage weapons. A warrior who uses a +8 weapon and a hp trinket will find himself far more effective in grinding than another with the same build but who uses a +9 weapon but has no hp absorb items.

Relics provide a nice way of shuffling attributes around to make your character more oriented towards pve when you decide to grind, or towards pvp when there is a need for it. Depending on your build and your where your interest lies, it may be a good idea to have accessories that allow you to switch between pve and pvp modes. This goes for weapons and clothes as well.