Board Thread:General Discussion/@comment-2600:387:1:810:0:0:0:41-20170907133032/@comment-24.145.242.26-20170908225614

Add 100 friends and visit them each daily. You get 50 coins per friend, up to the lesser of 50 or your reputation level. Then you get additional coins for each charge on a friend's board. They add up quickly.

As mentioned before, banishing monsters helps. Three cheaper monsters or 1 expensive monster = 300 coins. If you time travel, you get more items to use for banishing.