Before I played any of the Elder Scrolls games, I was really into World of Warcraft (WoW). My main character was an orc warlock. This build was inspired by the play style of that class.
For Race, to optimize your abilities (especially, early game), choose Breton, Dark Elf, or High Elf. Going by WoW lore, Humans and Orcs can also become warlocks.
For Standing Stone: choose the Mage Stone in early levels, then convert to the Atronach Stone. This is purely for gameplay reasons because WoW did not have standing stones.
The general idea for playing a warlock is your primary focuses should be on the Destruction and Conjuration schools. Specifically, focus on fire spells and summoning daedra. These are Skyrim's counterpart to the warlock's specializations of destruction and demonology, respectively. I ignored affliction because there isn't a magic based equivalent in Skyrim. Poison alchemists are the closest, I guess, to it. Alteration and Illusion have many spells that reflect the abilities used by the Warlock class. So invest in them heavily as well.
For combat, hit enemies with high damaging fire spells such as: Fireball, Incinerate, and Firestorm. Conjure Seekers or Dremora Lords to help kill your enemies as well as shield you from attacks. For added protection, use Ebony Flesh and Dragonhide. If you need more crowd control, use Hysteria and other fear-based abilities. If you're running out of magicka use Equilibrium; it's the equivalent to a signature warlock ability in WoW called Lifetap. Other novelty abilities which mimic warlock powers are Waterbreathing, Summon Arvak. and Vampiric Drain (if you want to become a vampire).
For gear, Warlocks wear cloth (no armor rating) and can use staffs, 1-handed swords, and daggers. For enchantments use the ones that enhance magicka and schools already mentioned above.
The Warlock is all about acquiring forbidden/taboo knowledge to make themselves more powerful. They are not afraid to consort with the daedra, their minions, or other dark magical users if it means learning new spells. For this reason, warlocks should join the College of WInterhold and the Volkihar Vampire Clan. They are also encouraged to collect as many daedric artifacts as well as the Black Books of Apocrypha on Solstheim.