A few thoughts on what we shouldn’t do, in my opinion:
If you don’t want your students to translate in their heads when they speak…
DON’T include translation in your assessment. EVER. Real translation/interpretation is a very advanced skill and will come with time anyway.
If you don’t want your students to run through a sequenced list of conjugations in order to come up with the “right” form…
DON’T drill conjugations. (My Spanish 1 students don’t even know there is a chart of subject/verb sequences.)
If you don’t want your students to be able to explain a ‘g’ stem-changing verb while still using “yo teno” or “ellos tenen” to communicate,
DON’T bother explaining ‘g’ stem-changing verbs.
If you don’t want your students to think they’re not “smart enough” for Spanish because they’re not good at school in general,
DON’T teach or assess language as if it were history or math or science.
The bottom line is this: we’re teachers and we like saying things like “past perfect subjunctive in an unreal if clause” but unless our students are going to be language teachers, such terminology will profit them nothing. There’s a whole big world out there waiting to communicate with them, so let’s teach them to communicate!