C - First, pre-measure all your ingredients, put them in little bowls and double check them. That way when you are adding something on the fly, you don't have to worry about; "Oh, crap! Was that a half or whole teaspoon?!?".
this is a great tip not just for beginners but for eveyone. the french call it "mise en place", meaning evrything in its place. in other words prep. like mark said it means getting everything organized before you start. it actually speeds things way up if you spend the time in the beginning. another thing that i would do if the prep was complicated was simply write everything down that needs to be done and what time to start, how long to finish ect as well as any other notes. check things off when they are done,as it helps knowing certain things are finished.
