Traits of a Professional thief:
-Patient, wait for the perfect opportunity, case out the place they are going to hit.
-They have a specific skill set; pick locks, hack security systems, get away driver etc..
-Usually work in groups, one or two work as distractions or look outs.
-They have a plan of entry and escape.
-Usually have inside information about where they are going to steal from.
-Good criminals have fences or people to sell what they stole too.
A great example of "Professional Criminals" would be all the members of the Bling Ring. If you don't already know this was a group of teenagers and young adults who went around the Hollywood area and burgled the homes of several celebrities. It was believed that this group stole upwards of 3$ million in just under a year' things stolen included large amounts of jewelry, clothes, and cosmetics. Most of the items stolen were from Paris Hilton who's house was hit numerous times.