How do i index my flash drive and external hard drive on OS X 10.9?

Hey everyone,

This is my first post and my first macbook.

I have the Air '13.

I'd like to search my flash drive and external harddrive for files, but I can't seem to get them indexed as other people have recommeded in other discussions.

I have tried going to system preferences -> spotlight -> privacy and adding then deleting both the flash drive and external drive, but none of my attempts are working.

Can anyone help?