You can improve your listening comprehension for the IELTS exam or for understanding presentations and lectures when you listen for the very transition words you use when you're writing an essay or speech.
These transition words tell you what the speaker is trying to tell you that may not be very obvious. They may be trying to emphasize a point, relate to something they said earlier, illustrate a concept, etc. When you can identify the function of the transition words you hear, you're going to better understand what is being said.
Check out this compilation video for some short, helpful lessons to improve your listening comprehension in English.