One things magic can do is change the user internally. Magic can be an excellent resource personal development. Meditation alone has proven medical benefits, and is a gateway practice into so many different activities.
Another is influencing situations in a subtle manner.
Divination is a fascinating topic to me. So are different perceptual aspects, and some psychic practices.
Of course, there is a lot more to the list.
Some things which are dependent completely upon belief are evocation and invocation of spirits, gods, demons, etc. Also, spiritual travel is belief-based. Some people do not believe things like astral projection (opting for scientific explanations), while some actively participate. There is so very much which falls in this category.
Some things which magic cannot do are changing a person physically; bringing inanimate objects to life; creating something from thin air or destroying things; teleportation; flight; growing appendages; levitation; change eye or hair color; control other people; take over another's body; et cetera.
Also, remember that a spell itself is not magic. A spell is a ritual meant to direct the practitioner's will and focus to achieve a magical result. You can cast any spell you wish, really. But if you are casting a spell to turn your eyes purple, you're just wasting your time. But if you do the necessary effort of put energy "out there" according to your belief for success in your job hunt, you are going in a more realistic direction. The same thing about trying to have a magical result regarding other people: You cannot make that grump at work like you, but you can direct energy towards a more amicable situation.