OK, so it isn't the greatest post ever. I wanted a catchy title to get people in here to read it. It is hopefully a good post with helpful information.
With Tamriel Unlimited here and an influx of new and returning players upon us, I have seen several people asking for specific build advice. Often at least one person will mention the internet and Google. I just wanted to put a few things here as simple guidelines. These are mostly aimed at players that are not yet in the Veteran ranks.
Tamriel Foundry is a good source of player builds and theory crafting. I like to browse here and see what different things people are trying out.
Deltia's Gaming is another great source of information. In addition to class guides, he also has dungeon guides for all Vet dungeons that I highly recommend. In addition, he has one write up on skills every character should have available. It is broken down by class and weapon skills and is pretty useful and insightful I think.
In addition, you can of course just try the old tried and true google method. Looking for a 2h stamina templar build, well google exactly that and likely you will get some hits that may or may not be beneficial. There are two VERY important caveats to all this.
THIS IS ALL ADVICE ONLY and THESE ARE ENDGAME BUILDS
ESO really is pretty different from other MMO's in that you can be successful without using the "cookie cutter" or "meta game" builds. Also of note, the playstyle of each person that develops the build is likely different from yours. My advice, if you do decide to try a build made by someone else don't feel that you have to do it exactly as they do. Use their build as a foundation and tweak it to your play style. In addition, always remember that the 1-50 leveling experience is different from the "end game" content. Use the leveling process to try all the skills available to you. Respec if you need to, it isn't terribly expensive early in the game, but remember that in the end you will have many many skill points at your disposal. So, what is this "guide" all about then? Really I just want to point out some generic strategies you can employ and use to help you along the way.
First, when going through quests and grinding you will likely see that you are really only going to use 2, maybe 3 skills for the most part. Use those extra spots on your bar to level other skills and other weapn/class lines. Its also nice to have a "turn in" skill bar. Using an addon such as Wykkyd's Outfitter will help alot. Once a skill you frequently used is at max level, it is a waste of skill bar space when you turn in a quest. Swapping your bars out to all unleveled skills will help you progress faster. Also remember, you don't need the specific weapon type equipped for a skill to be on your skill bar, i.e. you can be wielding 2 daggers yet have impulse on your skill bar. On a similar note, try to always be wearing at least one of each armor type. There is no reason you can't easily level each armor type to 50, even if you don't put any points into the passives. Who knows, at some point you might change your style and build and want to use different armor. You will be glad that each type is already leveled.
Your goal when undertaking your 1-50 leveling experience is to experience all or at least as many of the different play styles available to your class. Figure out what you enjoy and what you feel comfortable with. Practice and understand all the skills. This will make you a better player in PvE and in PvP as well. Once you understand how your skills work, you can start thinking about what direction you want to take your character. Know is a good time to talk about what I mean by what "direction" to take.
Ultimately, there are three categories of builds, and I don't mean tank/DPS/Heals. You have magicka based, stamina based, and hybrid. With the changes in 1.6, hybrids are less effective, but still more than capable of completing end game content. Basically, the type of character is based on what type of skills you utilize. Class skill damage and effectiveness are mostly based on magicka (1.6 introduced stamina based morphs and the tooltip clearly states this). Weapon skills are stamina based with the exception of Restoration and Destruction staves. Mixing and matching is perfectly fine and effective, but there are some limits. For example, I don't see a Nightblade wearing all heavy armor, wielding a restoration staff, and using all Mage Guild abilities (magicak based skills) to be terrible effective. Understanding the natural synergy between resource pools and skills is vital to success.
So when looking to define and build your character, remember that first and foremost it is YOUR character. If you are leveling up to veteran ranks, don't tie yourself down. Test the waters on a variety of play styles, skills, and armor types. In the end you need to remember that you are playing a game who's ultimate goal is to entertain you. If playing the build that someone else says is the "best" build for your class is not fun for you, then you most definitely should not be playing it.
My final thoughts are more of a call on our veteran members (been playing awhile veteran not vet rank veteran) and new members alike to revive the class build thread. I will try to get a nice detailed write up for both my higher level characters and post them to maybe get the ball rolling.