There are many good ways to practice modes.
Start in a major scale position and alter the notes in that position to get the modes:
Lydian – raise the 4th
Ionian – return the 4th to natural
Mixolydian – lower the 7th
Dorian – lower the 3rd and 7th
Aeolian – lower the 3rd, 6th and 7th
Phrygian – loser the 2nd, 3rd, 6th and 7th
Locrian – lower the 2nd, 3rd, 5th, 6th and 7th
Do this for every major scale position you know.
Start with pentatonic scales and add the missing notes to get the modes:
Major pentatonic = 1 2 3 4 5 6
Ionian – add 4 and 7
Lydian – add #4 and 7
Mixolydian – add 4 and b7
Minor pentatonic = 1 b3 4 5 b7
Dorian – add 2 and 6
Aeolian – add 2 and b6
Phrygian – add b2 and b6
Locrain – lower the 5 and add b2 and b6
Do this in every pentatonic position you know.
Play each mode over a pedal tone. Use your low E string as a pedal and practice switching between various E modes. Use the order I listed above:
E Lydian – E Ionian – E Mixolydian – E Dorian – E Aeolian – E Phrygian – E Locrian
You can tune the low E to different pitches to practice in different keys.
All of the above exercises are working with the modes in parallel – they all start from the same pitch. This is the most important way to work with modes in order to get the sound and interval formulas in your ears and under your fingers.
Once you’re comfortable with each mode, you can go on youtube and find backing tracks for each mode in a variety of keys. Noodle over the backing track with whichever mode is appropriate. Work the mode up and down the entire fingerboard. Spend a lot of time working up and down the strings rather than across the strings in a pattern.
For derivative mode practice, you can practice scale harmony and modes at the same time. You have to know scale harmony, though.
In C, you would play:
Cmaj chord – Cmaj7 arpeggio – C Ionian
Dmin chord – Dmin7 arpeggio – D Dorian
Emin chord – Emin7 arpeggio – E Phrygian
Fmaj chord – Fmaj7 arpeggio – F Lydian
Gmaj chord – G7 arpeggio – G Mixolydian
Amin chord – Amin7 arpeggio – A Aeolian
Bdim chord – Bmin7b5 arpeggio – B Locrian
Do this ascending and descending and in every key.
Change the order of the chords/arps/modes to Cmaj – Fmaj – Bdim – Emin – Amin – Dmin – Gmaj – Cmaj.
Do this in every key.