Further to the post of grouping modes together - minors - Dorian, Phrygian, Aeolian, - Majors Ionian/Lydian - Dominant Mixolydian and Locrian as a minor with a b5. That is a great approach. I would take it even one step further into arpeggios and then add the extra tones.

Over a Maj 7 chord - you can play a Maj7 arpeggio which would highlight the 1, 3, 5 and 7 tones, as you play this arpeggio over the chord you can add in 2, 4, and 6 notes to add Ionian flavour or 2, b4 and 6 tones for a Lydian flavour. etc.

This takes away learning all the different modes and recalling them 'on the fly' you just look for the arpeggio tones of the chord you are playing over. I call these lily pads - a frog can do all sorts of radical backflips and whatever but he has to land on a lily pad to avoid falling in the water. In other words - you can play whatever you like but you need to land on an arpeggio chord tone to sound like you know what you are doing.

Jason.