How to prepare a Journal Club (or Methods) presentation? I recently gave a presentation that was poorly received by my PI. I presented a technique that I have been trying to master (Patch Clamp). My PI thought I was not adequately prepared but gave no further feedback.

I spent three days putting together my presentation and read chapters  (Springer books) and papers, listened to lectures on the subject--over two weeks.  I have been giving presentations since undergrad. I just finished my M.S. I hope to enter graduate school in Fall of 2012. 

I don’t know what I am doing wrong. What is a more effective way to prepare a talk or presentation? How much background reading is sufficient? What types of questions do ask yourself when preparing a talk? How do you know you have truly mastered the material?
(this is rather long: I wrote it for one of my students, who had a similar question)

BASIC UNDERSTANDING
When you're processing a paper, ask yourself:  


what is their precise problem formulation
what is their solution
what larger issue are they trying to address with their paper
Do (1) and (2) actually fix (3)
(for experimental papers) do the experiments tell a convincing story to bolster their claims. Be suspicious of what they claim unless the line of reasoning is clear. 


SYNTHESIS
Once you've done this for a set of papers, you should start trying to connect them together:


is there a linear progression of ideas ?
How do the tools connect up
Is there some way to simplify and explain what groups of papers are doing under a common theme ?


CRITIQUE
Once you have the above, then you can ask    


what are the gaps in what people are doing        
Are these gaps important or minor ?
Does some union of the papers essentially solve the problem ? if so, why and if not, why not ?
Are these papers even solving the right problem ? (this last point is both tricky and critical - it is very easy for a line of research to be internally consistent but get totally derailed from the original motivation for the problem)


DIRECTIONS

Now you're ready to suggest new directions and new ideas.

note that critique comes AFTER basics and synthesis - you must understand very well before you can judge.