Practice sessions should be 20 - 30 minutes at a time for each instrument.
Start each session with playing through whole programme for that instrument.
Record this if possible so you can listen back and then work on sections that still need fixed.
When fixing - break sections down into small manageable chunks, going over it SLOWLY, bar at a time.
End practice session by performing whole programme for that instrument with the accompaniment or backing track and again record so you can listen back to it to see if it has improved from the start of the session.
A good idea is also to perform to whoever will listen - Mum, Dad, Sister, Brother, Cat, Dog, Goldfish !!!!!!!
Backing tracks and Accompaniments are on here - LHS website - if something isn't here email me via the button below.