Use of the infinative

[Estudiante_de_Espanol]

One thing that has been confusing me a lot is when to use the infinitive of a verb in a sentence. Does anyone have any useful hints? I've been making a lot of mistakes in my writing by using an infinitive verb after a conjugated one. But it isn't wrong every time I do it which makes me even more confused. Any suggestions?

[muripic]

The infinitive in Spanish is tricky because in English it's used in a different way... I think that the most effective way to learn it is to learn verb phrases (in Spanish, perífrasis o frases verbales). For example:

After tener que, deber, poder, querer, ir a, empezar a, terminar de and many others, you should always use the infinitive.

Some examples:

Tengo que estudiar.

Debes llamar a tu padre.

Terminamos de comer a las ocho.

But there are some verbs that require a gerund, such as continuar, seguir, andar, estar. English speakers usually say "continuar a hacer", while the correct phrase would be "continuar haciendo".

Some examples of this would be:

Seguí estudiando durante dos años más.

¿Qué andas haciendo estos días?

There are more complicated cases. If you post some of your mistakes maybe I can be more specific, but in the meantime I hope this helps!

[Trellum]

I think muipic summarized it all so well.  I've noticed a lot students have so much trouble with the infinitive and the gerund, because in english they both look the same and have different function each in Spanish.  Just try to remember that gerunds are most of the time used to describe when something or someone is actively doing something, like for example: Estoy comiendo uvas.  While the infinitive tends to be more vague and versatile, like: Me gusta comer uvas. 

My advice?  Get more examples on how the infinitive can be used I'm doing that very same thing with dutch and to this day is the only thing that has helped me when I find difficult sentences.