Infinitive is when the verb is not conjugated. It is in the original form "andar, beber" and we use "to" to speak, to do. I like to dance.

Incorrect, after preposition we always use ing.

stop, remember, want, try..

consider, feel like, can't help, imagine, practice, miss ...

As the continuous form. I am studying. I was doing...

hate, like, love, prefer

I tried to lift that heavy box; it was hard but I did it,(effort) The door was jammed, so we tried hitting it with a mallet. (experiment)