I have found it difficult to practice in any useful way, thus my German level has plateaued. Will be interested to see if others have some useful ideas!

The most helpful thing I have found so is to practice speaking with other native English speaking people, ideally a few levels above myself. I can understand much much more this way, and actually have a conversation since they speak much slower and with a lower level of vocabulary. With Swiss/Germans I end up sat there completely lost...