He should have been on the attack more. He did well when he tied his taxes to Clinton's emails, but seemed to back down in every argument after that.
So, according to you, his only fault was not attacking Clinton more. Not anything listed by the OP. Well, I guess that tells everyone here enough about yourself.
All of those gaffes arose because he allowed Clinton to frame the debate, when he ought to have brushed off her attacks and focused on issues of substance, on which she is consistently incompetent. It is asinine that the moderator focused on whether or not a private citizen was sincere in his prescient opposition to the invasion of Iraq, rather than asking the individual who authorized the attack and continued to shill for it for a subsequent ten years. Given even a modicum of preparation Trump ought to have been able to flip all of these attacks against his opponent, but fell into the trap of being on the defensive.
1. Trump supported, publicly, the invasion. This is incontrovertible.
2. Please explain how Clinton is "incompetent" on "substance". Last time I checked she had a website with plenty of "substance" on it. Please explain how that is "incompetent".