The background helps tell a story

In our class, one of the first things the teacher does is project our "homework" pictures up on the screen and we discuss all our shots.  One of the gals in my class took a picture of her birthday cake which was in the foreground of the picture and very clear (shallow depth of focus) and then the background, which was blurry, was her friends casually talking on the couch.  Our teacher pointed out that this is a great way to take a picture if you are telling a story with your picture.  The characters in the back of the picture were very significant (almost allusive - yet explained what was going on).  It wasn't just her sitting there eating her own cake, but she had friends over to celebrate - who looked to be having a great time.

I really was inspired by this so tried to figure out a background story telling photo for myself.  This is what I came up with...

We are painting our living room, and my daughter normally practices piano in the living room, but we've had to move her into the hallway because of the painting.  As you see, the pan is clearly in view and she is blurry.  The pan and paint brush aren't really great subjects in terms of beauty, but seemed to tell the story.

I find photographing the color yellow to be very difficult.  Never crisp edges. I've noticed this with flowers.  So, the brush, where the paint is yellow, doesn't seem real crisp.  It may be that my focus was too narrow and so it's just not that clear.  Has anyone else had issues in shooting a particular color?