Como foi?

como foi?
Most Portuguese courses start by teaching the future tense (using IR).

Como vai?

That's because it's the simplest thing to learn. But in the real world you want to be able to talk about what happened a few minutes ago; what happened yesterday, and so on. And, this is NO BIG DEAL to do. You just need to have the basics of the simple past conjugation (the preterite perfect), but you also need to know the conjugation of IR/SER in this tense (irregular).

As soon as you can do some verbs in the simple past you can start talking about things that HAPPENED!

Let's do it.

How was your day?

The most important thing to say! Tourists never ask anyone how it's going or, how someone's day is/was. You can score BIG points being able to say things like:

How did it go? > Como foi?

This is the same as asking How was it? You can answer: foi bom, foi ótimo, foi péssimo ETC.

How did it turn out? > Como ficou?

Brazilians will use FICAR when talking about how something turned out like this: Como ficou seu carro novo? (How did it go with your new car?) / Como ficou a instalação? (How did the software installation go?). You will answer using FICAR like this: ficou bom, ficou ótimo, ficou péssimo ETC.

How was (did it go) yesterday? > Como foi/ficou ontem?

Now you can elaborate such as, we went shopping or, she was sick: Fomos ao shopping / Ela ficou doente. You can say it without IR or FICAR by just conjugating any verb that expresses what you did, like this:

I played tennis. > Joguei tennis.
I studied my Portuguese. > Estudei o meu português.

More complex examples:

We went shopping > Fizemos compras. (literally: we made buys)
She was sick > Ela passou mal. (literally: she passed badly)