Know the effects that magic use has on society. Unless the ability to use magic is something that everyone has to the same degree, it is yet another personal difference that will set magic users apart. You need to decide both how others respond to this difference and how magic users themselves respond to this difference.
Consider how society views the ability to use magic. Is it a stigma or an honor? And think about why this view is held. Religion might preach against some or all magic abilities. Maybe the religious institutions use the very magic that they preach against but call it something else. Another reason there might be a stigma is past misuse of magic ability. In my world, magic users ruled during one era and nearly destroyed the world. Many, many years later they are no longer persecuted but still cannot hold land or any positions of power other than advisory roles. Reverse these scenarios and you have some reasons for society to honor the ability to use magic.
Decisions made by magic users at one point in history might have major social implications. This is easier for magic users in positions of power. During their era of rule, my magic users mutated natural creatures to use in their wars. This had lasting effects on the already existing societies. Most of the new races died out, but a few flourished – creating new cultures who fight with and hide from, trade with, and are enslaved by the original civilizations. But even magic users who are marginalized can have affect the course of history. I have one such magic user who sought revenge against the gods who used and dismissed him. He stole an artifact and managed to banish the gods from the physical plane. That definitely had an effect on society – besides paving the way for the rule of magic users!
Gender roles might change when magic ability is involved. Maybe magic ability is different along gender lines. This would affect social roles and expectations. Are women who are serious magic practitioners less likely to take time off from study to have children? This would probably go against standard gender expectations. Will men loose the ability to use magic if they have children? Then they probably wouldn’t. These scenarios also mean that magic ability is probably not hereditary. Are magic users desirable or undesirable spouses? Do magic users typically marry one another or stay celibate? If you want to make a point about gender, this is a treasure trove of options.
The way magic users are educated can affect society. Large schools require towns to support them. Monasteries would probably provide community service to their communities and countries. The larger the place of learning, the more likely there is to be government influence. Apprenticeship and mentorship systems provide socially recognized roles for the students and teachers. Do parents pay for their children to receive instruction, are the children conscripted, or are they given up freely? This says something about how children and magic use are perceived. Maybe the education process instills a sense of duty to country, community, the balance of things, or other magic users. Any of these would definitely have an impact on the rest of society.
The point is, your magic user – even your group of magic users – does not exist in a vacuum. The greater their numbers and the greater their power, the more effect they will have. But don’t ignore the historic potential of the lone rebel! Magic ability is an integral part of your civilization(s) – whether honored or scorned – so consider how the ability has affected that civilization throughout history. At the very least, consider how it affects the present lives of people!