One simple thing would be to not allow the crossing of a jurisdictional line, like that of a city or county.
I remember two such stunts in my prior tenure in the DPRM:
1) College Park was cut in half by the dems, placing each in an adjoining district. This eliminated any student vote from being effective.
2) Again, later,the dems, apparently wanting more party purity, changed Connie Morella’s (R) district from solely Montgomery county areas to include Prince George’s county. That took her out the next election.
I’d like to see a rule where all districts must be rectangular with the exception of having natural boundaries like rivers or align with existing boundaries such as county lines.