Presentation difficulties

There are many difficulties to perform a presentation, every presenter would have some weakness in his presentation , Some of these difficulties or weakness :

1.  Low self confidant in front of others.
2. weak ability to speak clearly / loudly. 
3. weak ability to relay on correct information.
4. follow the right sequence of idea in his presentation.
5. weak ability to using presentation aids ( projectors / board )
6. lack of information toward presentation's  subject.