Well i'm by no means an expert because it wasn't until recently that I was able to correct the softness in some of my shots, and even still have problems with it.
I found out that it wasn't so much a matter of missin the focus completely as much as it was not focusing in the right area. For example, I'd focus on the eyes and have that locked then, then when recomposing the shot, I'd end up refocusing on something else without realizing it. So the damn buttons in the picture would be sharp as hell and the eyes wouldn't be. Look at the dark stripe thing across her shirt in the first pic. It looks as though that was the focus point.
Something else to consider is the focal length at which you're shooting. I see you shot it at a shutter speed of 125. I'm not sure at what focal length you were zoomed in at but unless it was no more than 50mm you're probably getting some camera shake as well.
I too found this out the hard way. Took what I thought were some great zoom shots of my daughter. Only to find everything soft, blurred and otherwise aggravating.
I then discovered that you really can't shoot at a shutter speed of 125 or so with a 200mm lens unless you're on a tripod. Now I try to always make sure that my shutter speed is at least twice the focal length at whifh I'm shooting. For example, if I'm shootting at 200mm , i'll set my shutter speed to usually 500 or so. That eliminates camera shake if the camera is hand held.
Looks like you're dealing with the same issues I had when I first started shooting again last year.
P.S. The first lens I bought was the 50mm 1.8 (for about $80). And shot everything that. Images were sharp considering the plasticky feel of the lens itself and depth of field was acceptable.
I've sensed moved up a bit with my lenses but still experience similar problems.
I picked up the 85mm 1.8 USM for around 300.00 and it stays on my camera 90 percent of the time. Great lens for not being L glass.
Ok, I got a bit windy there, sorry about that.
Hope this helps as I proudly profess I'm no technical expert. lol.
P.S. About the reflector. I thought it was
adorama, but now I realize i bought it on
ebay. It's a basic 43" reflector with a silver, gold, white, black reflector AND white diffuser. I think was 15 or 16 bucks.