Most of the earning ways are here, but i think you know better because you already earn the bitcoin from your bitcoins.
So why you take tension, use the same way of earning where you are earning, so no problem for you.
But if you ask from us, so my answer is now, you have a lot of bitcoins so should do investment or trading, both are best, but need knowledge, information and timing, than of course you will get better profit with fast and furious.