In order to predict the future, we look at the historic values from your car's range and odometer. Based on this we calculate a trend line which reveals info and predictions about the future.
E.g. Tesla cars lose an average of 50km range after 3 years.
In order to have a positive impact on this value and extend this expected range, you could take into account the following:
limit the times you use a supercharger,
do not charge your battery always up to 100%,
do not deplete your battery below 20% (so keep it between 20% and 90% as much as possible),
charge often, not for long periods.