Strategies for Language Learning
In learning something new the comfort zone is to already know 80% of what it is you are attempting to learn. That is, when reviewing or working on acquiring new language skills 20% should be new challenging material. For example, when sitting to review vocabulary the review would consist of 80% words that you know and 20% words that are novel or you are struggling with.
If, in quizing yourself, you find that you are getting 95% of the words correct, then the pacing is too easy. However, if in quizing yourself you are getting 50% of the words wrong, then you are going too fast.