If the soap is soft like cream cheese right out of the fridge (or softer), you'll have lots of trouble if you try to cut or bevel the soap. If you can press gently with your finger and feel the soap start to make a dent, it's too soft. A wire cutter tears through the soap, and a knife sticks badly. A potato peeler or similar beveling tool just smears the edges rather than cuts a shaving.
The soap needs to have a firm but yielding texture -- like mild cheddar cheese -- to cut and bevel well. This is when you can press moderately firmly without leaving a dent, but you can feel the soap give a little under your finger. This is the point at which I like to cut and bevel my soap.
It's also an option to cut your bars at the "mild cheddar cheese" stage, but wait to bevel until the soap is much firmer -- more like aged cheddar or even parmesan. At that point the soap will barely yield or won't yield if you press it hard with a finger. Soap this firm will bevel nicely, but it probably cannot be cut easily if at all.
As a friend often says, "Practice makes better!" You won't get good until you practice, make mistakes, cuss a little, and try again until you get the hang of it. So pick the worst looking bar you have and get busy!
Remember -- this is not brain surgery ... it's only soap.