After I wrote about the problems with too much detail in presentations, I have started to grow more and more wary about it. Two things that lead to too much detail are lack of preparation and unfamiliarity with the content. One solution to these problems is focus. Focus on the audience, where do you want to take to audience? Why should they come with you? What's in there for them? Be ready to answer the "so what?" question. In case you are a graduate student or a professor at a conference, you might want the audience to spend their time analyzing your idea, to alert on possible errors or to suggest possible improvement; you want to raise awareness about your research.
If you dip your audience in detail and clutter, they might not be able to differentiate the important from the not important. Take a look at this video about awareness.
The video is trying to prove how hard it is to focus on many things going on at once.
You need to help navigate throw your topic to avoid this type of distraction. For that you need to know your material. Knowing your material is essential your presentation but it is not all. The key is to focus: focus on the preparation, focus on the audience.
Distill your material to get the core message and the supporting points, three supporting points are enough. Segment your presentation to favor focus and your supporting points. Forget the Introduction- Motivation- Body- Conclusion scheme, that's laziness, not focus. That scheme doesn't help to navigate. That is the same thing the other 99 presenters are doing. So if you are trying to raise awareness, you are just one more doing the same thing. Maybe that's what you want, but if it is, then do yourself and the audience a favor a don't present. Present to make a difference, and free people for the evil detail that pollutes scientific talks.
You have heard this before, less means more. Of all the simplicity quotes out there, this is my favorite one:
It seems that perfection [or simplicity] is attained not when there is nothing more to add, but when there is nothing more to remove.Talk preparation is so much about what to leave out as much as what to leave in.
—Antoine de Saint Exupéry
Now, knowing your material makes you separate detail from supporting point. You cannot present without supporting your argument. This can't be emphasized enough. In scientific talks details are confused with support, we think that if we show overwhelming amounts of detail, we will convince the audience. Not true, this will only overload the audience working memory and thus will cause you to lose it. You are having trouble deciding whether a piece of information go back to the audience and what they already know. Will that piece of information resonate with the audience enlightening them to grasp my core message?