A good way to approach the memorization of modes would be to assign numbers instead of note labels to the tones of the modes. The sharps and flats would be altered from the IONIAN or major scale.

IE:

IONIAN   1,2,3,4,5,6,7,8 (Although Ionian may have been a gapped scale without the 7th.

DORIAN    1,2,b3,4,5,6,b7,8

PHRYGIAN   1,b2,3,4,5,b6,b7,8

LYDIAN    1,2,3,#4,5,6,7,8

MYXOLYDIAN   1,2,3,4,5,6,b7,8

AEOLIAN