Here's something that appeals to my engineering mentality in its symmetry. With the exception of the first change, where the 3 and the 4 are reversed, as you go down the list you only need to alter one note. The numbers represent the number of half tones from the previous note, starting with the root.

Type of seventh/# of semitones between the notes

MAJ7=Root + 4+3+4
AUG MAJ7=Root + 4+4+3
DOM7=Root + 4+3+3
DIM7=Root + 3+3+3
1/2DIM7=Root + 3+3+4
MIN MAJ7=Root + 3+4+4
MIN7=Root + 3+4+3