Im trying to get 5* gear to get pass HoH.
Best way to get crowns
Playing the game. Nearly every run you do nets you crowns.
Put it on Elite if you want crowns faster.
The Jelly King and Roarmulus Twins offer you more crowns than most other runs and once you know what you're doing, are relatively fast. (Also, every 15 JK tokens you get, you can buy a piece of Jelly Mail and sell it to a vendor for 3,500 cr, increasing your profit even more.)
If you meant "how do I make crowns fast and without any effort," drop $10 on the game and sell your energy. Sadly there's no other way you can get rich quick because then everybody would be rich!
You can always ask guildmates to invite you on a FSC run but make sure you pull your own weight so they will invite you more times in the future. If FSC is too hard, I would reccommend Jelly King runs on Elite like Addy said.
This is probably the most frequently asked question on these forums --- hundreds of times. Try searching Google for something like "earn crowns site:forums.spiralknights.com".
The guild Lancer Knightz has detailed data on the crown payouts of missions. So you can choose your missions more wisely perhaps.
Perhaps Skepticraven will chime in with some of his recent studies too.
*Cough* New Recruits *cough*