Learn Hardcore Greek: Προσπαθώ να είμαι συνεπής και να μην αργώ στη συνάντηση. - I try to be punctual and not be late to the meeting.

Modern Greek doesn’t use an infinitive the way English does. Instead, it uses να + verb (the so‑called subjunctive structure) to express things like to be, to go, to do, to not be late, etc.
So να είμαι = to be / that I be, and να μην αργώ = to not be late / that I not be late.

What exactly does Προσπαθώ mean—I try or I’m trying?

Προσπαθώ is present tense and can cover both:

I try (in general / as a habit)
I’m trying (right now / currently making an effort)
Greek often relies on context to choose between these English translations.

Why is να repeated: να είμαι … και να μην αργώ? Can you say it only once?

Repeating να is the most natural and common way when you have two different verbs:

να είμαι (verb: είμαι, I am)
να μην αργώ (verb: αργώ, I’m late / I delay)
You can sometimes omit the second in casual speech, but keeping it makes the structure clear and sounds standard.