So far this is what I have picked up in a typical Assassin's Creed assassination.
1. Find view point
2. Eavesdrop some 2 goons talking
3. batter a guy for information - and then kill him
4. Assassinate guys or capture flags (To prove you are worth it) for informers to give you information.
5. Pickpocket some guy.
6. Assassinate some guy
7. Save citizens for the hell of it.
*Some of these you can do more than once*
I am on my 4th assassination and so far, they have all pretty much fell in those steps. It is quite long so doing basically the same thing over and over in an assassination can become boring. Also, the combat/A.I. is quite bad. If you are surrounded by tons of guards, no need to panic because all you can do is stand still and they all just sit there staring at you for like 5 seconds then 1 of them will make a move, but you just kill him with the counter attack technique and wait another 5 seconds for another to attack and so on until you either kill them all, or the few alive piss their pants and flee.
The game is very innovative in some aspects but kind of fails in some more in the more simplest of things or things we kind of expect to see in games now.