I am glad that the jury is taking a lot of notes. It is important, and you will see the prosecution to do this, do draw a timeline of events and a visual of where the evidence is to make a determination of what happened.
Witness testimony is important and in most cases every witness will have some things that are correct and others that are not. It is rare that one is completely lying or one has everything absolutely correct, especially when there is conflicting evidence.
Contemporaneous testimony - such as 9-1-1 calls - can be inaccurate though we live with the legal fiction that they are completely reliable. For example, I believe certain facts in Zimmerman's call to 9-1-1 is inaccurate, especially the description of Martin with his hand on his waistband and that he is on drugs or something. This, in my mind, is evidence that Zimmerman was preparing a self-defense claim ahead of time, and I am sure the prosecution will argue this.
Anyway, click here for my timeline.