What Randy said...... plus (and I'm going to focus for the moment on Knox's defence team, plus points related to the joint defence of Knox/Sollecito):
I think we can separate this into two different categories: procedural errors, and errors in the way the case was presented/argued. Most of Randy's points fell into the first list, and to that list I would again say that the single biggest fault in the whole saga was Dalla Vedova's agreement to take the case in the first place. He should, without doubt, have known that he was not the right person for the job. The professionally- and ethically-correct thing for him to have done was to turn down the case, and spend a short time using his general knowledge of the Italian law scene to draw up a shortlist of lawyers who truly were suitable.
On the presentation/argument side, I think that the overwhelming majority of the damage was done in the Massei trial. I think that both defence teams badly messed this trial up, and once they'd done so, it was an uphill battle from then on. In specific terms, they could and should have done all the following things: demolish Curatolo's credibility (a ludicrously simple phone call to the out-of-town disco operators might have effected this all on its own); demolish Quintavalle's credibility; demolish pretty much all of the forensic evidence from its identification/collection stage onwards (probably by calling in a number of internationally-renowned forensic scientists to show conclusively how tainted and worthless it was); focus much more on time of death (again, using top pathologists to explain in detail the implications of the stomach/duodenum evidence on ToD); cover off the coerced false"confession/accusation" properly and conclusively* (once more, using experts in the field to explain things like the Reid technique); use the telephone/computer evidence - particularly in relation to timings and most likely locations (again, proper heavy-hitting experts required).
There are lots of other areas (the break-in, the bathmat partial print, the post-murder actions/behaviour of Knox/Sollecito) in which the defence teams (in my view) made similar errors. In all of these areas, it's my belief that a far, far stronger defence case could and should have been made in the Massei trial. So, in addition to the headline errors, I think this was (with apologies for the idiom in relation to a stabbing murder) a case of death by a thousand cuts for Knox and Sollecito. It's my belief that had the defence teams nailed all of these areas in the Massei trial, then even if Knox and Sollecito had been found guilty in this first trial, the defence teams would have stood a far better chance in the subsequent appeals.
* Of course this shouldn't have been necessary in the murder trial, but since the same triers were hearing this evidence owing to the crazy decision to try the Lumumba slander charge at the same time, it cannot have failed to make an impression on them regarding the murder-related charges. Therefore, I don't think the defence teams had any option but to attack this issue forcefully, since its presence clearly stood to significantly impact upon the murder charges.