Writing an instrumental

I'm trying to write a guitar instrumental that has a classical/Spanish feel to it... I'm wondering what scale will be best? I've been told that A Phrygian is good for Spanish sounds (actually... any Phrygian is), but at the moment I'm more leaning towards classical.

And when writing the music, should I use chord fingerings that are in the scale or just play single notes?

I know that if you employ more minor scales in your playing it will have a classical feel to it. Can't say for chords though.

simply play from the heart and the song will do the rest

I think CS's advice is better than what I put down ;)

A good thing to do to get in the feel for classical music is to LISTEN to classical music.

Not just sit there and listen to it... listen and study at the same time. Ask questions as to why he is moving to certain places in the song with certain chords. Ask why he play ssomething after something else.

You need to understand classical music before you can just write a piece with a classical feel.