The answer to this question will vary greatly depending on your age, your relationship with your mother, and where your life is headed right now. If you are about to get out of jail, attempting to stay clean would be a good way to keep your mother happy. If you’re in college, graduating would be a good way to make her happy.
If you’re specifically asking about how to make her happy on Mother’s day, the easiest thing to do is call her. Hearing from you will make her incredibly happy if you’re on good terms but don’t get to talk much. If you’re not on good terms, perhaps a letter to start. Reach out to her in some way, but if your relationship is beyond repair, then maybe just stop worrying about making her happy.
There are different things that you can do to make your mother happy. You need to know first what your mom wants. Does your mom want you to graduate from college? If you answer yes, then this is something that you should do. Does your mom appreciate it when you have meals together?
Spend time with her at home. You can order takeout or just cook your own food. What matters is that you are going to bond with here. This can be enough to make her happy. Take note that all moms are different. Something that will be very important to one mom may not have the same effect on another mother.