IMO
Seeing The Relationship Between Elements
Lets take the problem apart:
I. The Elements
Do you really understand the elements?
Ex: Is the structure and purpose of the diff eq. clear? Does it make sense to you intuitively(can you really feel it, or is just taken for granted?)
II. Relationships
The relationships you are alluding to are logical relationships. I think you are being overly critical of yourself and your peers are simply memorizing the mathematical machinery (in the diff eq case) which leads you to believe that they "see" something you dont. But if for example you failed to notice the importance of the fundamental theorem of calculus and the rest of the class was "like,you know, duh!" then you could be missing practice (dont really understand the elements) OR you should go through a logic book, it should help reinforce the basic relationships among all thoughts, thus making it easier for your mind to catch on to complex trains of thought (by linking the basic logic "train cars"). Hope this was coherent, let me know if i should re-write it (just came out of 50 min session of looking at stereograms).
p.s.- Raymond Smullyan has an excellent book on logic, i would look it up. It has helped me in the past (plz dont make the assumption its too easy before trying, basic logic=not very basic) 
!
