My forte was sightreading. Did it every day for about 1 hour. Now my teaching load is quite heavy and I've been dealing with a lot of beginner intermediate students. I sat down the other day and my sight reading was terrible

I was appalled.
So now, I've set aside time in my schedule to practise site reading - EVERY day. And that's exactly how you get good with it.
As already mentioned:
1. Have a plethera of music at your disposal (the net is very good for downloading music in the public domain).
2. Make sure you don't know how the music goes (you don't want to be using your 'ear')
3. Play through the piece only once. Then move on to the next piece.
4. Always start with something easy - even grade 4 standard - and work your way up.
5. Learn to interpret music as patterns - just like we no longer spell out every letter in a word, we can also read music in scales, chords, sequences and not note for note. This can only come with practise and lots of it!
6. Read music away from the piano - hear it in your mind. Do this frequently, as this will also help you see music in patterns.
Sight reading should be a part of your every day practise. You can't practise a lot of sight reading unless you have a lot of music - so the real challenge is: WHERE do I get all this music from?
1. Teachers
2. Local library
3. Internet
4. Own collection
5. Friend's collection
You can buy a whole library of music from The Sheet Music Archive for $19.95 US dollars. This is a BARGAIN price.
http://www.sheetmusicarchive.net/index.cfmHappy sight reading!