Dual Talent Specialization is one of the best things that has happened to WoW in a long time. Sure, we've had lots of nice and pretty content, and sure we've had complete reviews of talents and classes, but dual specialization changed the game.
And not only the game has been changed by dual specialization, also the social factor of the game has been altered since this feature is in. Grouping in any possible way you can think of has become more flexible, and a lot less of a strain on anybody wanting to organize something that requires grouping.
Don't have enough healers? Oh hey, Mr Shadow Priest, can you please come as holy for this run? Don't have enough tanks, oh hey Miss Ret pallie, can you stick a shield on?
And those are only two of the more common examples. If I look at encounters and the higher end raiding content, you can now bring a far more varied group of players to an instance, and though I do think that they're not entirely there yet, it has been a large step to 'Bring the player not the class'.
Veneretio had a blog today about dual specing as a tank specifically for raiding. But of course the whole dual spec also exists outside of raiding.
In this post I'm going to alter the questions slightly and approach them from the non raid specific perspective. You can be the alt, or the new player who doesn't know yet, or maybe even the more experienced player who really just hasn't settled on their second spec yet.
(I could personally fill 4 specs easily, disc PVP, disc PVE, holy PVE, and shadow, but hey Blizzard isn't there yet.)
Questions to ask yourself before Specing
1) What sort of content do you normally play in?
Certain roles and specs are fairly raid oriented, and other specs are more solo oriented, whereas there is still PVP to consider as well. And though the lines between these 3 have faded a little, if you want to be good at the content you enjoy it is a good idea to use your talent points accordingly.
2) Will you play mainly PVE or PVP?
PVE (Player versus Environment)? Go to question numbers 3 through 6.
PVP (player versus Player)? Go to question numbers 4 through 7.
3) Do you have any idea what you want your main role to be in the game?
There are 3 main roles in World of Warcraft. Tank, healer, and dps. Not every class can play multiple roles, and there are even less classes who have the option to change into all 3 roles just by changing their talent points.
If you play a class that can be played in different roles by changing the talents, and you haven't decided on which role you like most, I would suggest to start with dps. This is a role that can be carried easier in a 5 man instance, so if you do make a mistake it can often be caught by one of the other dps in the group. Whereas if your a tank or healer, and you make a mistake, groupmembers may start falling over dead.
(This is not to say that there isn't a difference between good dps and bad dps, so dps don't fall over me all together now. But you sort of have to admit that it's a lot easier in a dungeon to carry a mediocre dps than to carry a mediocre healer or tank.)
Playing in a dps role will give you an easier opportunity to observe the other roles a bit, and see what they are doing. To see if you would like what they are doing, and to see if you want to try it out.
At a certain point there really is no other choice then to just go ahead and spec into a different role to really get the feeling of it though.
4) Do you have any idea what you want your main spec to be?
If yes, easypeasy, go stick your points into your first spec tab. Wahoo, one spec done.
If you don't know the answer to this question yet I can advice to look up some different specs for your class, and just start trying them out. There are quite a few good places to go to for some class advice, but one place that a lot of people use is Elitist Jerks.
On their forums they have advice for all classes in the game, and often you can find a thread that discusses which talents are best within each talent tree.
5) Does it matter to you how easily you get a spot in a group?
As it currently stands there are far more dps in the game, than there are healers or tanks. So even if your main spec is dps, if you want an easy time to get into groups you want your off spec to be tanking or healing.
If you have a choice between all 3 different roles (paladins and druids only) find out which role is most asked for on your server and spec accordingly. I know on my realm it is far easier to find a tank than a healer, but I've also read about it happening the other way around.
6) Which type of PVP do you play?
Arena and battlegrounds can require two completely different specs. When I go into an arena on my priest I will spec a lot more into the survivability talents, whereas if I go into a battleground I can often get away with a bit more healer heavy spec.
Find out which specs are good for the type of PVP you want to play, and figure out which specs perform best for your class in this.
7) Which classes do you team up with in PVP?
Depending on the composition of your pvp team you might want to decide on a different spec than the standard for your class. If you have already 4 dps in your team, it might be really handy to play the healer. Even if the ideal spec for your class would perhaps be dps.
Another example is if you go into a 5 man arena where the other 4 players of your team are all already heavily specialized in interupting it might be sensible to put the balance on dps a bit more.
8) Does your guild need specific specs?
Sometimes you will find yourself in a guild that is really short on one spec or the other. If you look at high end raiding this doesn't even limit to spec, they are even looking for specific classes.
If you find yourself in a guild where there is always a shortage of tanks or healers, it's often a good idea to have at least one of your specs to be one of these two.
On the other side if you find yourself in a guild where they do a lot of PVP in their spare time (or even as the main focus), it's nice to have a PVP spec at hand so you can step in and give your guildies a hand.
9) Which spec do you enjoy most?
Even though you can optimize for just about every aspect of the game, in most cases this is really the only question you have to ask.
Not only does this often decide whether you are found, in PVE or PVP content, it also decides your role, and with that your main spec, and sometimes even your off spec. (wahee PVE disc/holy ftw).
Often playing the spec you enjoy most makes that you are better at it than at other specs. So while you can stick a dps in a healer spec for the situation you're in. And this person might even enjoy it for a change, in the end it is much easier to excel in something you really enjoy doing, instead of something you were forced into because of the situation.