My concern, like WC's, is about the decision to change to IFR.
Bimbling along in glorious VMC, no problem. One little cloud - so I fly through it, still looking out the front and being "VFR".
As it gets cloudier/foggier, there comes a point when I should conclude this isn't VMC, and change to flying proper IFR in IMC. I've taught myself to announce (out loud) "Now flying IFR" and to DO that.
Sometimes it's 20 seconds after takeoff, sometimes part way through a long flight, but it's important to make that decision, quickly and firmly, and stick with it
I remember long years ago flying along just under a cloud layer, watching the treetops getting closer. I got quite uncomfortable, before I said "blow this" and climbed into the cloud.
The FAA IR test doesn't really do that - you know you're going to transition to IFR pretty soon, and have an "adjust time" while putting on the hood.