Secondly, sets. There's a LOT of sets. So, here's some links to help you decide which ones will work for you.
Let's start with a link to a "one size fits all" approach. So not min/maxed, but a "you really can't go wrong with this" approach.
ONE SIZE FITS ALLNow that does use a trial set, and his suggestion is to use Order's Wrath if you don't have that, but there are many other options, and depending on your class some obviously stronger options. It's almost like we could do with a tierlist...oh, wait, thanks to Mr. Skinny Cheeks, we have that
TIERLIST FOR DD SETSKeep in mind that list is for update 42, so Azureblight has been changed, but everything else mentioned is still up to date. He also has a Monster Set list on his site too, if you don't want to run a mythic, but bear in mind that Stormfist has been nerfed to Oblivion in this latest patch
MONSTER SETS**************
Next, skills. Depending on the class you play, how do you know which skills are going to work for you? Luckily Ninja Pulls has created an excellent series of guides on that exact topic. (Except Wardens. Whether that might come I'm not sure, as Wardens tend to be used as healers in endgame, not DD. I love playing a Warden DD, but I do think they lend themselves more to an Oakensoul Build - more on that soon.)
GENERAL OVERVIEW ON DPSTEMPLARSORCERERNIGHTBLADENECROMANCERDRAGONKNIGHTARCANIST