GPU mining (only do this after your blockchain is synchronised): Type in "ethminer -G" and press "enter" and then you should start mining with your GPU after building a DAG file which can take around ten minutes. There can be problems at this point. For example the program might say that you have insufficient memory on your Graphics card to mine the with Ethereum's Ethash algorithm. If this is the case you can still mine with your CPU or go out and buy a new graphics card! You can see our graphics cards and compare their return on investments here and check out our guide on how to pick an ethereum mining graphics card here. We've also added a guide on how to build your ethereum mining rig.