Whenever an English to carries the sense of in order to, Spanish must have para. The "to" form of the verb alone is not enough to include that meaning.
Hemos hablado para resolverlo.
English can drop the in order: we have spoken to resolve it. Translate that directly and it does not work in Spanish. The test is whether in order to fits.
Hemos hablado para intentar resolverlo · Estoy aquí para verte · Te he llamado para hablarlo
A Spanish speaker with basic English might say "I am here for see you". Once you have heard the same mistake a few times, you can assume it comes from Spanish.
Put estar into the line past and you get an alternative to the plain imperfect. Most of the time they are interchangeable.
Comía / Estaba comiendo · Estaba tomando un curso de español
Sometimes one fits slightly better, and that is something you pick up naturally while practising. If people favour one in a given situation, you will notice.
English also uses -ing to build adjectives out of verbs: to interest gives interesting. Spanish has its own endings for that.
-ar → -ante · -er / -ir → -iente
English even preserves the rule in its own Latin words: salient is exactly this ending on salir.
Es irritante · La luna menguante, not "menguando"
Vivo is also an adjective meaning alive, so un ser vivo works too, but viviente is the -ing form.
English says swimming is healthy. Spanish says to swim is healthy.
Bailar es saludable · Nadar es saludable
English hides this, though Monday is "moon day". Spanish makes it obvious.
Estoy explicándolo / Lo estoy explicando. The little word can attach to an -ando or -iendo form as well as to a "to" form.
Explicar holds the same -plicar from Latin plicare, to fold, so to explain is to unfold.