I'm a big advocate of keeping an informal written record of what happens in your business.  I'm not talking about a “dear diary” daily entry of all the mundane details.  I'm talking about recording what you've learned when you go through a difficult situation.  It can be any situation that teaches you something.  Just write down what you learned.  Now, if you're like me, you're probably thinking, “You've got to be kidding.  This is huge.  I'm never going to forget this.”  And you don't — for several months.  But you let a year go by (or two, or five,) and you'll have forgotten all about it.  But just pique your memory and you'll say, “Oh, yeah.  I remember that.” 

I keep a notes section in the back of my planner.  I write a note every now and then as something noteworthy comes along.  When I have time, or when things are slow, I review those notes.  I also use them when I have a sticky situation and don't know exactly what to do.  It's interesting to me that the direct answer to your problem is probably not found in your notes.  However, what happens for me is I read something that sparks another train of thought that leads me to the solution. 

I had a situation just the other day where it worked for me.  I had dealings with a person who made me uncomfortable.  I don't know why.  He was kind, outgoing, witty, funny, smart, engaging — and something wasn't right.  As I was looking through my notes, I came across the quote, “When the character of a man is unclear to you, look at his friends.”  Now that's not new to me.  I've shared that quote with almost everyone I know.  What's odd, is when I read that quote I saw it in the context of my current situation.  I thought about the associates of this person and knew exactly why I was feeling uncomfortable.  From that insight, I knew exactly what to do.

Maybe you're saying, “I don't have time to write a book about what's happening in my business.  You don't have to.  You don't need lengthy explanations of what happened.  You were there. 
You'll remember.  Just write something that will trigger your memory of
the event.  Sometimes just a few sentences will spark the answer to a
complex question.

Who knows.  Had I not had that record maybe I would have stumbled upon the answer in another way.  But having a record was certainly a shortcut.  It also gives you a pat on the back when you're having a bad day.  You read those things and think, “Wow.  I'm pretty amazing.”  That always cheers you up.  No matter what your motivation, keep a record.  You'll be glad you did.