I agree with learning the Major and Minor scales, all forms of the minor scales. Harmonic..Melodic..etc.. It would be benificial in learning the Diminished Scale and I would also practice the Chromatic scale. I would also have an understanding of the Diatonic Harmonies. For example I would record this Diatonic Progression and play the scales across them as they go by. I..ii..iii.IV..V..vi.vii(Half Dim) Which equals out to be in the key of C
C(Major) D(minor) E(minor) F(Major) G(Dominant) A(minor) B(Half Diminished)
I think this would get you set up for learning and understanding the modes.
I feel this helps you get a better feel and ear development also, when you can hear the scales played across a chord progression, I hope in some small way this is helpful to you!!