Optimising Qlikview means increase the speed of the application for any selection did by client in access point and also increase the speed of the application reloading for scheduled time i.e decrease the time of loading.
1)you need to remove unnecessary columns from Edit script(delete unnecessary columns,drop unnecessary tables)
2) Reduce joins to less number
3)Remove synthetic keys,Tables and also remove circular loops
4)Load data using qvd's
5)if possible reduce the set analysis expressions in front end and do it those in script level.