Although the Art of Magic is not limited to Rituals and Spells, certainly these two practices are a large - and interesting - part of it. Although it has become common to use these two verbal terms as synonymous, they are not the same thing at all but two completely different practices that each serve different purposes.
A Spell, is the act in which we strengthen or mutate our psychosomatic state by exploiting our vital energy. This is done mainly with meditation and words that help in self-concentration and usually candles, crystals, herbs, aromatic incenses and other auxiliary objects are also used which also serve the purpose of self-concentration.
A spell could be characterized as a very direct approach to the goal, since we work completely alone without the help of other persons (although they can also be done in groups) and without invoking or seeking help from Deities and spirits.
A spell is also a rather "rough" and not time-consuming task, or can be made such. By "rough" I do not mean that no attention is paid, but that it does not require special preparations and time. Some spells can be performed even within a few minutes and generally the time of performing a spell does not exceed an hour or even half an hour.
THE CEREMONIES are directly connected to the Deities and to religion. They are usually performed to seek help, guidance or recognition from the Deities, or simply to honor Them. Ceremonies are always performed with the appropriate honors and preparations, they include many items, most purely symbolic and not directly functional.
Unlike Spells, Ceremonies are usually performed by groups where some basic hierarchy is observed in the distribution of the tasks of its execution (High Priests, Priests, Hierophants, etc.), but this does not mean that it is wrong to perform them even by one atom. Their duration is long, starting from a minimum of 1 hour and sometimes reaching up to a whole day. (Some very special Rituals may last more than 1, 2, 3... days).
In summary, we could say that a Spel is something we can do every day and more than once a day, while a Ceremony is something special that doesn't happen every day. The Spell is performed - as a rule - to serve and satisfy our daily, social and material needs (financial, professional, emotional, etc.), while the Ceremony is to serve and satisfy our spiritual and religious needs (religious holidays, marriage, baptism , initiation etc).
This is, of course, a very general division since spells can be performed for spiritual reasons just as Ceremonies can be performed for social reasons.