Coin Making Strategies

Trophies
This is a volume based strategy.  Snipe trophies during periods of low demand and sell during high demand periods (TOTW, GC, etc).  Sniping trophies is typically most successful late in the night and early in the morning.

Legend Collectibles
Prices on Legend collectibles drop when the Legendary Pack is available in the store.  Snipe collectibles for high value players during this time and sell after the Legendary Pack is unavailable.

Game Changers
High value GC players can be sniped for a bargain on days that the GC event is running.  Resell days after the GC event has ended.

Legends
Prices for Legend players tend to drop during promos.  Use this time to pick up the highest rated Legends and sell after the promo expires.

Elites
Snipe 90+ OVR Elite players off the AH.

Promotions
The first couple days of a new promotion (Halloween, Thanksgiving, Christmas, etc) the collectibles necessary to build the rewards go for premium prices.  Instead of saving the collectibles sell them.  However, this is a common strategy and prices will drop quickly, therefore do not post auctions for more than 4 hours.

Position Players
Early in the season there are a limited number of high OVR players in some positions (kickers, punters, etc).  Snipe these position players and quickly resell.

New Players
When new players are released (TOTW Hero, Legends, etc) there is a premium on them in the auction house.  If you can build the new player in the morning and post him in the evening you can turn a quick profit.

Note on Content Drop
At midnight eastern time new content is dropped in the Auction House and again every 5 minutes 1 second thereafter.  EA has changed the drop timing multiple times so this is likely to change again.