Both Preguntar and Pedir mean to ask.
Preguntar is to ask a question.
Pedir is to ask for something.
As luck would have it, pedir sounds like pedicure (something you ask for)
and preguntar sounds like pregnant ( a condition you'd be wise to not ask questions about)
Here is a visual to make my point:
Pedir
 |
| This question is asking FOR something |
Preguntar
 |
| Use Preguntar when asking normal questions. |
