As I’m not a Nokia Expert, I can give you general guidelines.
Take 1 cluster as a typical one.
Make NBR audits (very critical, in the swaps usually the NBR is either mapped from before or planned as new) in both ways you need to make sure you eliminate the distanced cells/redundant and add the first and second tier cells - this will balance the cluster, improve the CDR PS CDR.
Change the cell-access (sel-resel parameters) (increase the required measurement to access the cell) parameters to improve the CSSR/PSSR.
Check the formulas of the KPIs (I encountered so many cases where the formulas themselves were incorrect).