I've decided to work through the keyboard binders for my church choir as my piano sight-reading practice. Sometimes, I'll start by running through the harmonies. Other times, I set the metronome on and barrel right through the music. And then other times, I just pick a comfortable tempo to read at.
One thing I should do more is sight-sing. When I sing or conduct, I do try to sight-sing. Let's just say that it's a work in progress.
I still have my sight-singing book from university: Boosey and Hawkes 333 Elementary Exercises In Sight Singing - Kodaly Choral Method (Standard). It's been helpful - when I remember to use it.