Is there any practical method that will assist one to greater rapidity in sight-reading?
The best way to become a quick reader is to read as much as possible. The rapidity of your progress depends upon the state of your general musical education, for the more complete this is the better you will be able to surmise the logical sequel of a phrase once started. A large part of sight-reading consists of surmising, as you will find upon analyzing your book-reading.
To Gain Facility in Sight-Reading
What is a good plan to pursue to improve the facility in sight-reading?
Much reading and playing at sight and as fast as possible, even though at first some slight inaccuracies may creep in. By quick reading you develop that faculty of the eye which is meant by "grasp," and this, in turn, facilitates your reading of details.
[ACCOMPANYING]
Learning To Accompany at Sight
How can one learn to accompany at sight?
Develop your sight-reading by playing many accompaniments, and endeavour—while playing your part—also to read and inwardly hear the solo part.
The Art of Accompanying a Soloist