Let's say I am spending 250 USD to mine a coin of worth 330 USD, selling it immediately doesn't give me a big profit. If I am selling the same coin for 500 USD then thats a good strategy.
(amount spent on mining per coin in FIAT) : (Value of the coin)
when you get a good ratio convert the coin to FIAT.
But you never know how long you have to wait for price to reach $500.I would suggest sell some and save some.Since you have 'lots of coins' you can keep selling even when you get $50 profit.But dont forget to save atleast half of your coins for future