No soldier dies in an announced war except for careless soldiers.
Lack of preparation is the most common error of speakers, it is also brings the most negative consequences; a good preparation give you don’t do it, these kind of things would happen:
When developing a topic that we want to share with the audience, we always have to take into account the applicability of our arguments. Why is the topic so important? How will the listeners get a benefit of it? How the content of my speech can be applied into real life?
If the speech is only informative, it will not have a significant impact on the listeners. They will perceive it as another discourse, irelevant, or maybe as something that they have heard before.
This an important error when it comes to a thesis defense in most of the Universities and academic institutions. They demand their students to have updated data. You have to be careful with this to fulfill the academic requirement established by the institution.
It is true that not all areas of knowledge should require at least five years updated database, but when including a statistical data this consideration is very important. The jury will probably compare it with statistical data of other years.
The speech interactivity does not necessarily include the direct participation of the public, although it led your event to be more attractive and dynamic. Interviews and question and answer sessions are a good example.
If the technical part of the event is related with the participation of the listeners, the speaker can include a passive interaction, for example, rhetorical questions. Also, he can make some questions to its public before the development of the speech so he can used the answers later as a part of his arguments.
We all want to show our best attitude in front of a microphone, surprising others with our overflowing charisma and joy, however it is not an instant skill. There are event directors who pressure novice speakers to have excess of energy while presentation when it is not something natural of them. The result is an overacting show, a farce. It effectively manages to draw attention to the public, but not because the message but for the sad and ridiculous role the speaker is doing at microphone.
So please, be yourself always. Avoid using a «mask», do not create a personality that does not belong to you. If someone has said that you lack charisma when speaking, try and practice with the different tones of your voice to find the indicated one that reflects security. Remember, the public loves a natural and relaxed speaker.