What Not to do in a tech talk

Based on my experiences in attending tech talks and developer conferences recently, and watching YouTube videos of those, which I miss out. I came up with a list of certain things that most people do, and which brings down the interest level of audiences in the talk. This is my effort to sum it all down, and provide solutions to them. This post is continuously updated, so if you guys have points to add, just comment below.

Update

Added points 8 and 9 in During the Talk based on suggestions.

Before the talk

1. Boasting about your talk. It is perfectly normal to discuss with people about your talk and grab audiences, but you should never keep boasting about your talks. This puts in a negative impression about the speaker, even if your talk is a beauty
2. Do Rehearse. Many times, developers are confident about the talk they are about to give, because they might have been working on those stuff for years, but before you go on the stage, make sure that you have rehearsed. This will increase your timeliness and boost your confidence.

The recent trends in developer talks is to upload them on youtube, so every single mistake that you do in your talk is stored somewhere digitally, forever. So, make sure you are well prepared

During the talk

1. Don't be unplanned. Don't start off without an agenda, target audience, what is inside the scope of the talk and what is outside of the scope, and finally what the audience should expect from the talk. It is a good idea to let people know the usefulness of the talk they are attending to.
2. Don't exceed timeline. A talk scheduled for 45 minutes, should complete by the end of 46th minute. And yes, that includes the question answer session, discussions and greetings. For every extra minute you consume, you are doing it at the expense of number of people sitting there.
3. Don't be stupid lecturer. The audience in tech talks come to gain from other's experience. So, when you are given an opportunity to talk that's because the talk-selection committee believes that your experience will help others grow and develop applications in your domain, by taking advantage of your experience. Talk about something challenging, how it should be handled, what are common myths, misconceptions, confusions and how to fix those things. People are there not to listen, what they read in the book titled "XYZ for dummies".
4. Avoid temptations. Usually there is a subtopic in your talk, which is your favorite. Probably because you are a guru in it, because you build it; the reason is irrelevant. What is relevant is that you should always avoid the temptation to go into too depth of the topic, stick to the timeline and provide a neutral view of it. Stressing too much on a topic creates a non uniform talk and the audience might loose grip at times
5. Avoid Coding there itself I have seen a lot of engineers who start coding while speaking. This should always be avoided, without exceptions. Coding On The Spot or COTS, makes audience loose interest, takes too much time, and if you believe in Murphy's rule, something will go wrong, while you are working there. In any of the cases, audience won't like it. If showing coding is absolutely necessary, make sure you have a video for that, all planned with sub-titles or narration. You can always give your audience a homework to do, which will make sure that the session is alive, even days after.
6. Avoid too much code in slides Showing parts of code, or snippets is absolutely fine, but make sure it is well balanced with the text/graphics in your slides. Keeping a slide mostly occupied with snippets is a bad idea.
7. Identify hecklers There are always some people in the audience, who have a question for every line you speak. Avoid those people taking your talks. That ways, you will save time, annoyance. Reserve some time, usually 5 minutes at the end of your talk, for clarifications of doubts. Also, at this point, I would like to introduce you to Google Moderator. You can create a "meeting" on Moderator, and give its shortened URL to the audiences in the beginning of your talk. For every question the audience has, they will create a question in the moderator. Others can like, Vote up, Vote down and possibly answer that question. At the end of the talk, take the most voted questions or the questions that you think needs to be addressed at that time. For rest of the questions, you can answer them later after the talk
8. Internet Connectivity and Demo If you are displaying web pages - make sure they are all loaded in tabs in your browser before you start. Also make sure you have offline copies in case internet stops working.
9. Know thy system Make sure you know where your files are - do not spend half your talk searching your file system for those files you want to show.

After the talk

1. Don't stay behind the fort People will come to you after the talk to clarify things that got left in the session. Depending on the time you have (and you must be prepared for it) you should talk to them and try to solve their issues. They are the ones who were most attentive in your talk and took the pains to see you after the talk. They are your potential fans, and make sure you do not displease them :-)
2. Don't compare Under any circumstances, you should never compare your talk with any one else. This gives a very bad image of you.
3. Don't give false promises If you have shared your email/ moderator URL (and you should) in the talk, you must keep checking them frequently for the next couple of weeks to see if someone has reported any problem/ doubt in your talk.

As always, I am open to more inputs. Kindly share your ideas and thoughts by commenting below so I will keep on updating this post.