A fuerza de esmaltar vasijas, mejoré en cerámica.

A fuerza de means something like by, through, or as a result of doing something over and over / with sustained effort.

In this sentence, it suggests that the improvement happened thanks to repeated practice:

• A fuerza de esmaltar vasijas, mejoré en cerámica.
• By glazing pots over and over, I got better at ceramics.

It often carries the idea of persistence, repetition, or even sheer effort.

Examples:

• A fuerza de practicar, aprendió. = He learned through lots of practice.
• A fuerza de insistir, lo consiguió. = By insisting again and again, he achieved it.

Because a fuerza de is normally followed by an infinitive when the next idea is a verb.

So:

• a fuerza de + infinitive

That gives:

• a fuerza de esmaltar
• not normally a fuerza de esmaltando

More examples:

• a fuerza de estudiar
• a fuerza de repetir
• a fuerza de trabajar

You can also have a fuerza de + noun, for example:

• a fuerza de paciencia = through patience
• a fuerza de esfuerzo = through effort

Esmaltar means to glaze or to enamel, depending on context.

In ceramics, it means applying a glaze to pottery before firing it.

So here:

• esmaltar vasijas = to glaze pots / vessels

This is a specific ceramics verb, so it sounds more technical than a general verb like pintar.

Vasijas means vessels, pots, or ceramic containers. It is a fairly broad word.

It is not exactly the same as:

• jarrones = vases
• ollas = pots for cooking

Vasija is a more general term and fits well in a ceramics context. It can sound a bit more neutral or slightly technical/literary than some everyday words.

Because Spanish often leaves out the article when speaking about things in a general, non-specific way.

So:

• esmaltar vasijas = to glaze pots / pottery vessels in general
• not specific pots already identified

If you said:

• esmaltar las vasijas

that would mean to glaze the pots/the vessels, referring to particular ones already known from the context.

This is similar to:

• leer libros = to read books
• vender coches = to sell cars

Mejoré is the pretérito indefinido in Spain, also called the preterite in English grammar terms.

It is the 1st person singular form of mejorar:

• yo mejoré = I improved / I got better

This tense presents the improvement as a completed result.

So the sentence means that, after all that repeated glazing, I ended up improving.

Because mejoré focuses on the improvement as a completed change or result, while mejoraba would describe it more as an ongoing process or background situation.

Compare:

• A fuerza de esmaltar vasijas, mejoré en cerámica.
  = By glazing pots over time, I improved at ceramics.
  This highlights the result.

• A fuerza de esmaltar vasijas, mejoraba en cerámica.
  = By glazing pots, I was improving at ceramics.
  This sounds more like a process in progress, and is less likely unless the wider context needs that nuance.

So mejoré is the most natural choice if the speaker wants to emphasize the outcome.

Mejorar en means to improve in / at a subject, skill, or area.

So:

• mejorar en matemáticas = to improve in maths
• mejorar en español = to improve in Spanish
• mejorar en cerámica = to improve in ceramics

Here, en marks the field or area where the improvement happened.

Yes, mejoré en la cerámica is also possible.

There is a small nuance:

• en cerámica sounds a bit more like in ceramics as a skill/discipline
• en la cerámica can sound a bit more like in the area/field of ceramics

In many contexts, the difference is very small, and both are understandable.

The version without the article can sound a little more streamlined or general.

Here it refers to ceramics as a craft, discipline, or skill, not just the material itself.

Spanish cerámica can mean:

• ceramics as an art form
• ceramic ware / pottery
• sometimes the material category more broadly

In this sentence, because of mejoré en, the intended meaning is clearly I got better at ceramics / pottery-making.

Yes, it is natural and fully understandable in Spain.

It sounds a little careful or well-written, rather than very casual everyday speech. That is mainly because of:

• a fuerza de
• vasijas
• the overall compact structure

A more conversational version might be something like:

• De tanto esmaltar vasijas, mejoré en cerámica.
• Después de esmaltar tantas vasijas, mejoré en cerámica.

But the original sentence is perfectly good Spanish.

Both can express the idea that something happened because of repetition, but the tone is a bit different.

• a fuerza de emphasizes effort, persistence, repeated action
• de tanto emphasizes sheer quantity / doing something so much

Compare:

• A fuerza de esmaltar vasijas, mejoré en cerámica.
  = I improved through persistent practice.
• De tanto esmaltar vasijas, mejoré en cerámica.
  = I improved because I glazed so many pots / did it so much.

In many contexts they are close, but a fuerza de feels a bit more focused on effort and perseverance.

Yes. It does not have to be positive. It simply means that something happens through repeated action, pressure, insistence, or effort.

Examples:

• A fuerza de presionarlo, aceptó. = By pressuring him so much, he accepted.
• A fuerza de repetir el error, lo empeoró todo. = By repeating the mistake again and again, he made everything worse.

So in your sentence it has a positive result, but the expression itself is neutral about whether the result is good or bad.

Yes, absolutely.

Both are correct:

• A fuerza de esmaltar vasijas, mejoré en cerámica.
• Mejoré en cerámica a fuerza de esmaltar vasijas.

The difference is mainly about emphasis:

• putting a fuerza de esmaltar vasijas first highlights the cause/process
• putting mejoré en cerámica first highlights the result

Spanish is fairly flexible here.

Not exactly. The closer translation is:

• I improved at ceramics
• I got better at ceramics

If you say I improved my ceramics, that sounds unnatural in English unless you mean specific ceramic pieces or some aspect of your ceramics work.

So for a learner, the best natural English equivalent is:

• I got better at ceramics

A few points may help:

• fuerza: the ue is a diphthong, roughly FWER-tha in most of Spain
• esmaltar: stress on the last syllable, es-mal-TAR
• vasijas: in most of Spain, va-SI-has
• mejoré: final stress because of the accent mark, me-ho-RE
• cerámica: stress on rá, ce-RA-mi-ca

In most of Spain:

• z in fuerza sounds like th in thin
• j in mejoré and vasijas is the strong throaty Spanish j

So a Spain pronunciation would be roughly:

• A FWER-tha de es-mal-TAR va-SI-has, me-ho-RE en ce-RA-mi-ca.