This one is hard. You have to be a scumbag to win. Simple Fact: It takes you less time to rob your enemies of their gem shards than it does to actually mine for them yourself. Now, how do you do this effectively? You get a hero that has 5x Marauder Skills all up to Level 5. This way, when you steal someones mine, you will steal all 100% of their gem shards. All you have to do is wait and make sure that their mining session is almost done. You do this by finding mines, tapping on the arrow to the right, and seeing how much longer they have until their mines are completed. You can win entire gem shard competitions without having mined a single minute. I’ve seen it done, and I’ve done it myself. But be prepared to have a ton of angry people hunting you down.