It depends on the kind of collection you have.
If you have a nice, high grade collection auctions, a website or
ebay with near trends buy it now/best offer can be effective, maybe the occasional coin show.
If you are going with an average collection midgrade collection, mixed method
ebay and coin shows are probably best.
If low grade,
ebay auction or host event for novice collectors, probably hard to break even unless you have massive volume eg. Asyn.
I am saying this based on observation of some high grade sellers and ownexperience with low/mid-grade selling. I am up overall, but that is largely due to some good buy/sell of mid/high/nclt coins. Not counting time of course.