Okay, let's see about this...
First off, the sewing job looks very good. The seams and lining look as tight, even, and secure as they should, which needless to say is important in a purse if you don't want your shit falling out of it. Since you have mentioned that you had sewn it by hand instead of machine, I find this especially impressive.
The blue, purple, and black fabrics complement one another in color, though at first glance the patterns seem to clash.
As for the strap, I would have used a ready made leather strap in a solid black with metal rings . It would have looked more professional than the fabric strap you used. However, it is very good for a first attempt, speaking from my limited experience in the medium.