If the violation are few in mumbers. Try to do manual adjustment on the routing,
If it is huge in number, try to find the reason why it is occuring, ex: try to place your Blocks and Std cell optimally or try to change the floorplan to have more routing area for the signals
could u give me the rough procedure to manually fix the pre route short and spacing drc violations. also my design is having only std cells and no macros. i am getting 35 pre route short and 17 pre route spacing violations.