People frequently speak of alegrías, but the broad group to which all the similar styles belong is called cantiñas. This includes alegrías, romeras, caracoles and mirabrás. As these styles are all based on singing, we can simply refer to guitar playing in these styles as cantiñas.

Here are three ideas for picado in E major, C major and A major over beats 7-10 of the cantiñas rhythm. I see most singers doing cantiñas in C, but you really have to develop this style in all three keys if you want to accompany (Javier Molina and others also played in G). I've been trying to develop my picado lately, and cantiñas is a great context for picado. You can expand these ideas beyond the rather ordinary confines of beats 7-10 by starting a bit earlier (e.g.: between beats five and six) and leading up to the first note indicated here. Better yet, draw on these ideas for inspiration and come up with your own!

Key of E: The second idea finishes on the fourth string, but it can obviously end on the open sixth string, like the others.

Key of C:

Key of A: You might prefer to play the second idea an octave higher.