In Part-1 I have explained two basic rule here i am going to explain some other rule.
3. Proper Media Selection
People should should proper medium of communication. simple message and some feedback can be send by face-2-face communication. big written messages are always complex and people don't read it, so try to make it short. important and things to do early can given and written on notice boards and something like that.
4. Problem of Word Selection
Sometime bigger message make people avoid to read such things, sometimes word makes it difficult to understand to people. try to use simple sentences and simple words that convey message to lots people even if they are not good in that language or media. if sender using complex words then it will be difficult him to get reply from the receiver and that becomes barrier in communication
5. Noise
Noise always becomes barrier in communication, because it interrupts message being sent to receiver. noise can inside of you mind that distract you from listening carefully to source or it might be external like people talking seating near you in auditorium or background noise while talking on cell phone. you can avoid it by changing your place for some time and concentrating on speaker.