So the problems with most silver players are the following:
- bad/no map awareness
- bad farming skills
- dying to much
- bad positioning after the laning phase
Simply try to improve on these points by somehow forcing you to glance at the minimap every few seconds and starting a custom game alone and just farm minions.
Dying too much is because you are not aware what your champions / teammates are capable of. You can improve on this aspect by seeing how good streamers are positioning themselves and how they act after the laning phase.