I used to be rubbish at sight reading until Grade 3 (UK grades) when my teacher gave me an ABRSM sight reading book. It contained little snippets of songs that I had to sight read. I did between 1 and 3 a day and I improved to the point where I got full marks on my exam. It's sometimes good to look over old songs as well or try the first couple bars/lines of a new song, depending on your skill level. Hope this helps!
Sight reading skills by: Ido from www.pianoplayit.com
That's is a great question. Scanning ahead a few bars is one of the important skills that should be taught concerning sight reading.However, it is difficult for beginners to adapt to it.
A beginner has to deal with lots of parameters and signs: the notes, rhythm, dynamics, articulation etc.
Having the experience with many students by now I can say that it is almost an impossible mission for a beginner to anticipate. Actually I find it unnecessary during the first year and I prefer to focus on other basics.
On the other hand, if a student develops a good reading skill quickly, I will gradually work with him / her on scanning ahead.
The first thing I do is to give my students pieces that are relatively easy for them to read. ( Click here for dozens of easy piano sheets). With the help of these pices, the students don't have to work too hard to figure out the notes; they can play the notes and are free to scan through the next bars. Gradually I give them more difficult pieces.
One more thing that I do is explaining the theory behind the music. When a student understands the logic behind the notes he will read better and more fluently. Of course, it takes time to learn the whole story of piano theory, but it will help you to read and play better.
Music in many cases is built upon patterns. You can find melodic lines that repeat in different variations, arppeggios, scales, chords and more.
When you become familiar with these patterns you will find that they occur in many pieces. It will help you to understand what is going on in the next bar and to read more fluently.
To summarize, The sight reading skill develops through time. After reading hundreds and hundreds of piano music sheets. It can be taught almost right from the start, but it depends on your natural tendency to do it, and it should be improved gradually.