Watch the Modes of the Major Scale online guitar lesson by Fareed Haque from Modal Improv Survival Guide
Practice jamming on each mode of the major scale so you can get an idea of how each mode sounds and feel, and to get an idea of the MOOD each mode creates. Find some way to get a bass drone happening on each root note, so you can just run up and down the scale and hear how each note changes from mode to mode. Each note changes its relationship to the new root note and that changes its sound. So for ex a D in 1st mode is the 9th...sweet! but a D in 3rd mode is the 7th - tough! and a D in 6th mode is an 11th - cool! so the same note changes function and mood as you change the modal root.