Quite a bit. I found Jacques Soustelle's book Daily Life of the Aztecs: On the Eve of the Spanish Conquest to be informative and a decent summary of what is in the Florentine Codex coupled with other sources, but /u/400-Rabbits may have a better recommendation.

Depends on what you mean by "regular citizen;" in a metropolis of >200K people there was quite a bit of diversity. If we're just looking at the group of people typically called "commoners" who made up the bulk of the population, the macehualtin, we still have an enormous range of variety between professions, dedications, ages, and sexes.

For instance, even though Tenochtitlan was an urban society dependent on food imports, it was still an important agricultural center too, through the use of chinampas, the "floating gardens" (actually artificial islands) which revolutionized post-classic agriculture. These formed a ring of canals and raised fields around the main city, which of course required dredging and maintenence, along with other more stereotypically farming tasks, like acquiring and spreading fertilizer (night soil, in this instance, which was deposited in specific containers along city streets and collected by workers later).

There were also long-distance traders, pochteca, who (mostly) lived in their own calpulli (barrio). While they would often be gone for months (even years) at a time, the more typical schedule for trade for the rest of the populace revolved around the 5-day market schedule. Cortés, in his 2nd Letter, said of the market of Tlatelolco (the sister city Tenochtitlan annexed in 1473), that it was "twice as large as that of the city of Salamanca, surrounded by porticoes, where are daily assembled more than sixty thousand souls, engaged in buying and selling ; and where are found all kinds of merchandise that the world affords...." While he mentions this occurred "daily," the modern interpretation was that he was probably referring to the major fifth day markets (a phenomenon which continues to persist in parts of Mexico).

It's not like the markets ever ceased though. Since Tenochtitlan was not only a dense urban society, but also the recipient of massive flows of tribute in the form of raw and finished goods, there was a constant bustle of trade in the markets, homes, and workshops. The city of Otumba, to the NE of the Tenochtitlan, has a decent archaeological record showing concentrations of leavings which indicate concentrations of workshops for gemstones, obsidian, and maguey, and we have no reason to believe Tenochtitlan was any different (even if the whole of Mexico City presents a bit of a barrier to thorough excavations).

Craft production would also take place in the home on a smaller scale, particularly when it came to "women's work" like weaving and ceramics. There was in fact a strong sense of separate spheres in Aztec life, which designated the male role as public and the female role as private. That is, a woman was expected to concern herself with domestic activities like tending the hearth, grinding corn on the metate, weaving, and looking after children, while the role of men was directed more outside the home. The barrios of Tenochtitlan, for instance, not only organized community life, but also acted as the basis for military life as well; men might be called up in the dry season to go to war.

Certain older men, particularly veterans, might also act as instructors in the telpochcalli, literally the "youth house," but basically a neighborhood school that all children would attend for a few years starting at age 15 (or earlier). For girls, this meant more basic education to supplement what they would be learning at home. For boys, the telpochcalli was a more formal boarding school, where they would spend a few austere years learning the basics of Aztec education (arts, religion, and particularly warfare), before leaving as adults to get married and form their own households.

Then there were the religious celebrations and ceremonies. The Aztecs had two interlocking calenders, a solar calender of 18 months of 20 days, plus 5 (the xiuhpohualli) and a more ritual calender of 20 periods of 13 days (the tonalpohualli). Each month of the xiuhpohualli had a particular religious festival associated with it, which might involve a day or two of ceremonies, or months of preparations (particularly if you were a priest). The tonalpohualli would also mandate certain observances as it progressed, which the "New Fire" ceremony held every 52 years when both calendars returned to their starting point (i.e., completed a "calender round"). Personally, I sometimes wonder how anything got done in-between all the singing, dancing, blood sacrifice, and tamale eating.

So there's really no typical day in Tenochtitlan, anymore than there is a typical day for any major city. Even within a certain class of people the cornucopia of professions, further divided by age and gender, was simple a feature of the complex stratified society of Mesoamerica.

Mictlantecuhtli mentioned Soustelle's book, and it is a classic, as is Bray's Everyday Life of the Aztecs also published in the 1960s. Not to get his liver up, but there a couple more modern recent books on the subject which I'd recommend: Carrasco's Daily Life of the Aztecs and Aguilar-Moreno's Handbook to Life in the Aztec World. Both are, as our skeletal friend points out, heavily in debt to primary sources like Sahagún's Historia General de las Cosas de la Nueva España (i.e. The Florentine Codex), particularly Book 10: The People, which lists a dizzying array of professions and social classes along with the expected behaviors of each.