Verbos sin sujeto al principio de la frase

Aprender idiomas es ... = Learning languages is ...
Para aprender idiomas tienes que ... = To learn languages you have to ...
Aprendiendo idiomas tendrás ... = By learning languages you'll get ...

Infinitivo = Ing verb

The examples above lead to many mistakes. You know that To + Infinitive translates as Spanish infinitivo, but when Spanish infinitivo comes at the beginning with no subject, it translates as an -ING verb. Therefore:

Despertarse por la mañana es duro.
Wrong: To get up in the morning is hard.
Right: Getting up in the morning is hard.

Para infinitivo = To + infinitive

To + infinitive at the beginning usually translates as para + infinitivo. A common mistake is using for + ing for this structure.

Para entrar en el país, necesitas un visado.
Wrong: For getting in the country, you'll need a visa.
Right: To get in the country, you'll need a visa.

Gerundio = By + Ing verb

The next case is less frequent: What if you start a Spanish sentence with a gerundio (-ndo)? You can't use just an -ing verb, but first you must add BY.

Reduciendo estos costes, ganamos más dinero .
Wrong: Cutting these costs, we make more money.
Right: By cutting these costs, we make more money.