After all, they only need someone who is at par with them. Become more evil, Dark Brotherhood will automatically contact you.
You will also be contacted by the guild, if you indulge yourself in killing random people.
Gray-Mane are fierce enemies of the Battle-Born. Or you can simply go to their main guild hall and join the guild. Help them slay these giants and they will lead you to their leader, Kodlak Whitemane in Jorrvaskr. You will encounter members of The Companions fight Giants. If you want to become werewolf, read How To Become Werewolf. If you gain trust of The Companions, you will join their inner circle of the most trusted members, who are Werewolves. If you were member of the Fighters Guild in Oblivion, choose to join this guild. They are mercenaries, good in combat, and are based in Whiterun. You will receive the membership of the guild, upon completing this quest. Enter the College of Winterhold and find Grand Teacher, Tolfdir. If you were member of the Mages Guild in Oblivion, you should definitely join College of Winterhold, because they are pretty close. You want to choose the path of magic ? choose to join this guild, based in Winterhold.
