5. How to get to capital cities without travelling
When you start the game, you won't be able to fast travel to any of the major holds - Markarth, Windhelm and so on. If you're in a rush and don't fancy riding there yourself, talk to the horse and carriage owner in the stables outside Whiterun (or any city for that matter) and he'll take you to whichever capital you choose for a small fee.
6. How to beat summoner enemies
Certain enemies use conjuration magic to call up support characters. A good example of this is the Draugr Scourge who has a nasty habit of conjuring up an Ice Atronach. The key to beating these guys is to ignore the conjured monster completely and focus on the summoner. As soon as he or she dies, their helper will die along with them.
7. How to join the Dark Brotherhood
So In Oblivion, murdering an innocent would attract the attention of the Brotherhood, but it's different in Skyrim. First you'll have to locate a boy called Aventus Aretino. His house is in the city of Windhelm, on the upper level, and you'll have to pick the lock to get in.
Once you've completed his quest in Riften, continue playing the game as normal and eventually a mysterious courier will deliver a note to you. When he does, sleep in any bed you own and your recruitment will begin.