The best thing you can do to keep sharp is to just simply PRACTICE!
Check the practice tips and materials page for my guides on practicing as well as a practice tracker.
Website with different levels of knowledge applied to note naming and fingerings. http://www.musicracer.com/ ALSO https://www.musictheory.net/exercises (use the settings gear to adjust the clef, range, and accidental usage)
Flute Trainer: http://www.flutetrainer.com/
Oboe Trainer: http://www.oboetrainer.com/
Clarinet Trainer: http://www.clarinettrainer.com/
Bassoon Trainer: http://www.bassoontrainer.com/
Saxophone Trainer: http://www.saxtrainer.musickramer.com/
Brass Trainer: http://classic.musictheory.net/86
Keyboard Trainer: http://www.musictheory.net/exercises/keyboard/999d
Blooket games!
Music symbols and terminology: https://www.blooket.com/set/6093f345fba5ed002840cff1
Treble Clef: https://www.blooket.com/set/608c191e17fd3a001bf418a0
Bass Clef: https://www.blooket.com/set/608bfc1ab4677b0021059804