Well, if playing over a minor chord... (Along with Dorian and Aeolian, pentatonic minor and blues version among other scales you could use). Another great tool is working with 3 easy to remember triads. The minor triad is 3 notes - A, C & E ... if it is a minor chord you work your way up with an alternating pattern starting with the kind of chord (so minor,major,minor...)... If it were a Major chord you were over it would be Major, minor, Major.
So for our example an Amin chord (remember the notes are A,C,E) you could play:
See they flip flop minor,major,minor,major,minor...
If it were a Major chord (A, C#, E) you could play:
See they flip flop major,minor,major,minor...
Try making up a "scale" build of only notes of these three options.