Firstly, remember that magic is not spells. Spells are a tool that some people choose to use in attempt to obtain a magical result.
Magic is change; it is change, either internal change, or change manifest in the external world, in accordance with one's will. Some people do this through ritual, mantras, sigils, spells, astral travel, working with entities, methods from the incredibly simple to the extremely ornate and elaborate.
As to whether spells work, the answer is that yes. Some do. Some do not. Just because something is written as a spell does not automatically make it do what it seems like it is meant to accomplish. This is the internet. Take everything with a grain of salt. There are plenty of spells here in the fantasy and trick sections, and many also which are posted in wrong locations, which will not work whatsoever.
Magic cannot do the impossible. It cannot change your physiology. It cannot make you shoot fireballs from your hands or laser beams from your eyes. It cannot directly control other people. It cannot teleport to a different world, either temporarily or permanently. It cannot reverse time or send someone back in time. It does not change memories.
So what can it do? Magical practice can be used for internal personal development. It can help a person explore who they really are, rather than seeing the mask they portray to themselves. It can be used to inspire courage, relieve and deal with stress, build a sense of self-worth. It can do so very much more.
Some people use magic to improve their finances, though this is a touchy area for some. People may use it to find love, or change the way others perceive them. It can be used to find a job more easily.
The best way to start is meditation. While it is not mandatory in every tradition, meditation trains the mind to focus. It has confirmed medical benefits. Deep breathing exercises have very good benefits as well, and many meditation exercises are about focusing on breath.
Generally, to meditate, one sits in a comfortable position with their back straight and their eyes closed in a quiet or relaxing space to block out distractions.
Depending on the intent of your meditative session, you may or may not choose to focus on something, but you would ideally let unrelated or unuseful thoughts simply pass by.
If you simply type "meditation" into Google, you will find plenty of useful results for techniques, as well as exercises and guided meditations.