The most important skill, whether you wish to perform, analyze, or just listen actively, is to be able to distinguish by ear among the various ajnas used in Arabic music. The Jins is the basic unit of melody, and maqamat are built from pathways among ajnas. If you don't yet have a great deal of familiarity with Arabic music, or the ability to distinguish and identify these ajnas by ear, I recommend visiting the Beginner Track, as an introduction to this section.
Identifying Ajnas is more than simply about distinguishing them from each other (whether by mood, melodic content, or interval relationships). It is about developing a relationship with the ajnas such that each one is immediately clear to you. When you first meet a person, you may identify them by their distinguishing characteristics. When you have seen them enough times, you no longer think of them as "the young lady with brown hair and glasses" or "the older man who likes to wear fedoras", but as your friends Mariam, and Dennis. This is how you must identify ajnas; without that sense of recognition (as opposed to figuring it out each time you hear them by going through distinguishing characteristics), any higher-level analysis is simply not possible. To develop that sense of recognition, the only path is by repeated listening over time.
This page points to pages with audio examples of each jins. The ajnas can be classified into 3-note, 4-note, or 5-note ajnas, depending on which scale degree (3, 4, or 5) is the most important secondary tonic/ most frequent modulation point. However, as you will see in the next section, melodies using these ajnas extend beyond the boundaries defined in this way. Follow the links on the right to the pages for each jins.
In all the 5-note ajnas here, the first and second scale degrees are identical, while the third note differs, being low in Nahawand and Nakriz (a half step), medium in Rast, a little higher in Jiharkah, and highest in Ajam, which resembles the western Major scale.
In all the ajnas here, the second scale degree varies, from lowest in Kurd, to higher in Hijaz, and higher still in Bayati and Saba (where it is a "quarter tone", and the third scale degree also varies, from low in Bayati and Kurd and Saba, to high in Hijaz. Saba has a lowered 4 (but the first 3 notes are identical to Bayati), making it one of the few ajnas that doesn't span a perfect 4th or 5th.
Sikah, meaning "3rd note" in Persian, has as its tonic the "quarter-tone" note, the third note of Rast. Mukhalif and Musta3ar are variants of Sikah--Mukhalif with a lowered 3rd, and Musta3ar with a raised 2nd. However, Mukhalif has a more distinct identity in Iraqi music.