How to use “se”, the subjunctive, the preterite, the imperfect, etc?

Please forget about grammar. If you know those words, pretend you never learned them. And if you don’t know them, good! Explanations about grammar rules, how to put together sentences, or the “whys” of the language may make us feel like we're learning and satisfy our curiosity, but they do nothing for our acquisition. Learning about the language is completely tangential to acquiring the language. And that’s not it. Being conscious about language rules leads to decreased fluency, since you are engaging the conscious part of your brain, which prevents the acquired intuition for the language from coming out unencumbered. Learn why in our answer to How am I going to learn grammar?.