He found an easily movable good (silver stemware), located in an reasonably accessible part of most every house (downstairs, usually in the dining room), using a crime whose punishment has lessened in severity b/c of its decline in perpetrators (cat burglary) & that he had mastered (stayed in great shape, was meticulous, taunted cops, etc).

Kind of hacked the system if you ask me. Of course he still got caught...

Stemware?

Candlesticks, goblets and the like.

1) Buy a big house.

2) Keep a lot of silver downstairs.

3) ???

4) Meet Nordahl.