Ahhhh modes. I hadn`t posted here in six years until yesterday, nice to see the topic still stirs up the dust around here LOL.
(1): Modes are like different seasonings for food. Major and minor are like salt and pepper. They do the job, and find a place in every dish. The modes are like garlic, ginger, sage, cayenne, etc...they have a unique flavor that makes them different. Some people like nothing more than pepper on a steak. Some people like garlic and crushed red peppers.
Each mode has it`s own signature, so to speak. It`s own unique sound.
(2) When I`m teaching my students modes, I will encourage them to emphasize the half steps at first to get used to hearing what makes the mode unique. Where the half step lies is what separates one scale from another (for instance, in a major scale the half steps are between 3 and 4 and 7 and 8. Move the 2nd half step to between 6 and 7 and you have a mixolydian scale. Emphasizing the half steps would bring attention to the flatted 7th, the signature note of the scale).
There are countless ways to look at the idea. Find one that makes sense and you`ll understand why and where modes are used, and then how to use them in your own playing