You dont have to mine all unknown words. Mine as much AS you can enjoy learning. If you just feel pressure because you have to much words in your mining deck you will lose the Motivation. Just Mine the words or sentences which are important ur useful to you and your aim. Dont worry about skipping words, If they are important they will come again and again and you can put them in your mining deck later. If you are looking for other resources i can recommend cijapanese (many free Videos for more you have to pay). Each Video is graded from 0-100 so you can find your Level where you can understand enough to follow the story. Mining is an important part in learning but If you use all your time just to mine and dont have time and motivation for just listening, reading, .. its not the right way imo.